As a former cable tech I know exactly what the OP is talking about. And as for access, yes utility workers have full access to your yard weather you like it or not, and if you don't like it we call the cops and you can be arrested. Calling ahead or even telling people to put their big a$$ dog away doesn't always work. People are often ignorant and do dumb things, like the guy that told his nice dog to "get'em" (in a joking way) but the dog still lunged at me and got wacked in the head with my aluminum clip board. I've also had a boxer corner me in a backyard and a German shepherd run at me from a neighbors house luckily stopping 10ft away thanks to a underground fence. if you have ever had a German shepard run full speed at you then you know the puckered factor that can create.
Now even though this is a problem in that line of work the chances are usually slim that you will be attacked. most techs I knew carried a long screwdriver or a crescent wrench, both are very effective. FYI, cable techs have no need for a 8in or longer screwdriver
As for defending against a dog, don't try and kick, a dog is faster on all fours and you will likely miss and leave yourself open. if the dog had a collar this is your best grab point, as long as you can stay away from the jaws you can control the animal very well from the collar. If controlling the animal is out of the question then it would be time to move to plan B. Just like human confrontations you don't want to kill someone's animal if it is not justified, basically you would need to be injured first before you could justify pulling a weapon. use something heavy and blunt first, use a knife or screwdriver if your life needs a savin.