I work for a nationwide telecommunications/cable/internet company and it is strictly against our policies for our installation and repair techs to accept tips. Sometimes they are offered tips and they are supposed to politely decline. Heck, they are offered all sorts of things ...but the rules are to decline.
These techs are union employees (as far as Verizon, AT&T, Qwest, etc are concerned anyway) and make a very decent salary (I manage a group of technicians and many make considerably more than I do!).
I am really shocked that Verizon lets their techs accept tips!