Bladenut: Here's my two cents. I'll try and keep them organized, but if I ramble, please forgive me!
AIRPLANES: The general rule for carry on is no more than a 3" blade. They also frown on serrations/sawteeth. Anything bigger I'd pack in my CHECKED baggage. Last time I checked, it was against FAA regs to carry pepper spray on-board a commercial aircraft. This is because it is pressurized. Don't even think about carrying one of those zytel/plastic knives onboard thinking you won't get caught. You may not, but if it is seen when they x-ray your bags, you will be charged with PREMEDITATED attempt to bring a weapon aboard an aircraft. After all, why else would you take a knife designed to defeat metal detectors aboard an airplane? As soon as you get to the airport, immediately go to the security checkpoint and go through it toward your gate. This checkpoint is where they will x-ray your carry-on bags and make you walk through a metal detector. The advantage to going through right away is that you are less likely to run across an armed individual inside the checkpoint than you are in the general areas outside it. In the bathrooms, use the stalls. This way you can close the door behind you while you urinate without having to constantly look over your shoulder. Take your carry-on bags with you inside the stall and hang them from the hooks (not on the floor where someone can reach under and grab your stuff while you are going!). NEVER let your bags out of your sight and never agree to carry someone else's bags (a stranger) through the security checkpoint. If they are carrying illegal drugs, YOU are busted! When I get aboard, I note where the emergency exits are and also pay attention to the stewardesses when they go over the emergency procedures during taxiing. I also read the card in the back of the seat in front of me (people look at me strange, but hey) that covers safety procedures and check under my seat to make sure my flotation device is there for overwater flights. I also try to know the general route the aircraft will be flying in case it were to go down. At least if I lived, I'd have a general idea of where I was. A small surefire flashlight could be invaluable on your person if the plane slid off the runway during landing or takeoff due to ice/snow. The emergency slides/chutes would deploy and your flashlight would help you find the exits easier, especially if there were smoke and no power. If travelling internationally, keep your passport on your person and not in checked baggage.
CARS: If renting a car, make sure it comes with a jack. I have been surprised several times when a rental car did not have a jack in the trunk. Try to get one that doesn't have rental car markings all over it. In some states, there are laws that require rental car agencies to not mark the cars in any way that indicate it is a rental. This helps make it harder for the bad guys to pick out tourists. It doesn't help if you leave maps on the seat though. If you are in your own car, your tag will give you away. Oh well. In my car, I always keep a mag-lite (the batteries outlast a "surefire"), a cell phone, and my carry knife (a 4" bladed Cold Steel "Voyager"). If driving across the desert southwest, I also take a couple of the liter jugs of water in case I break down or the engine overheats. A AAA membership could be worth its weight in gold. In cold climates, like when I lived in Japan or in the northern US during the winter, I keep a sleeping bag in the trunk as well as some snacks/drinks. Road flares are also part of the plan. Keep your tank at least half-full and top off when you can. Don't drive around strange cities at night. If you don't know the city you are going to (and you are flying there), take a cab rather than drive. Cabbies know where the bad spots are. If overseas, be sure cab drivers turn on the meter. This is especially true in the Phillipines, Korea, Thailand, etc.. It is not a problem in Japan or Australia. (Never get into a jeepney in the Phillipines by yourself).
HOTELS: Make reservations in advance. This way you won't be driving around looking for a place to stay in a strange town. Most of the newer ones have the metal bar that slides down across the sliding glass door to prevent its being opened from the outside. When I travelled to third world countries, I used to take a piece of broomhandle about two feet long and drop it in the track to prevent its being opened from the outside. I always take a rubber doorstop and place it under the door from the inside when I go to bed. This way, if someone has a key and tries to get in, I've got warning. Those cheap metal hangers in the closet also will serve as an alarm if you hang them from the door. You can get battery operated motion detectors for like twenty dollars. They will definitely give you a heads up if someone comes in your room, but not a whole lot of advance notice. The hotels all have policies regarding lost keys, namely that they will either replace the lock or rotate the lock with a room on another floor. In practice, almost none of them (in the US) follow it. They have insurance which covers them against lawsuits and it is cheaper than following their own guidelines. Sad, but too often, true. The doors with the key cards with all the holes are best. This way, if you lose it, no one can tell what room it goes to (they generally don't have the room number on it). Check the phone book as soon as you arrive and verify that the location has 911 service. Most do, but there may be some that still don't. Also, see if you can dial out on your phone without going through the front desk in an emergency. If you have serious trouble (an intruder trying to get in) and you decide to call for help, call 911, not the front desk. The front desk may try to solve the problem on their own in order to avoid adverse publicity. 911 will get the cops on the way. Then call the front desk. Lock valuables up in the room safe or the front desk's safe deposit box (if they have them-most big hotels do) rather than leave them in your room. The maids all make minimum wage and they have a real bad reputation (in general) for stealing valuables.
I guess that about wraps it up. I'm sure others will give their info and cover areas that I have totally forgotten. Remember, you can rarely be too cautious. It is not paranoid to think that someone may try to rob or roll you when there are people out there that try to rob/roll travellers. I might add that by following these basic precautions, I have never had any real problems, but I have seen others who ignored their security and did. Hope this helps. If it is all old news or not what you were looking for, feel free to make a voodoo doll of me and stick pins in it (but not too many!). JRF.
[This message has been edited by jrf (edited 05-02-2001).]