I've carried knives with clips on them in my back pockets for about 21 years now (Spyderco Police 1990-1998, Benchmade AFO 1998-2010, and a Spyderco Military 2010 to present). All have been tip-down designs, though I have no preference. I can "deploy" a tip-down blade just as fast as a tip-up blade, and tip-down seems a little safer should the blade open up in one's pocket. I don't believe I've ever had an occasion where I needed to pull my knife out and open it fast anyway, and I tend to think the whole "tip-up vs. tip-down" debate is only something armchair Rambos worry about anyway (my opinion only, so no one get your feathers ruffled lol). I usually keep the knife in my back left pocket nowadays, as I prefer to keep my wallet in my back right pocket, but in the past I've carried knives in my back right pocket. I like to clip it as far to my side as the pocket will allow. Losing the knife has never been a problem if the clip is tight enough. I don't like carring in my front pocket because when I sit down the closed knife jabs into my thigh, though this is only a problem because I carry fairly large folders. The only negative side I've experience to carrying knives in my back pocket is that the knife clip will scratch my car seat when I get in and out of my car if I'm not careful as I slide my butt accross the seat. However, I've found that carrying my knife in my left pocket has all but eliminated this problem.