In the tournaments I fish I don't use cull tags at all. I'm probably what a lot of guys would consider overly careful with the fish. I can take the extra minute or two take determine which fish needs to be culled, etc, without sticking things on them and what not. I also, when I release a fish, don't make them look like olympic divers and have them do 3 half-gainers in the air on their way back like I see a lot of both pros and amateurs do. I just feel like I owe it to a nice fish that give me a good time catching it to put them back with some respect. I'm no hippie or animal rights activist but I guess I think there is a bit of good-will mother nature might throw your way if you treat these fish nicely.
But back to your question and I think it's a good topic, totally agree with nets (although I do think it tests angler's skills in landing fish and fighting them correctly), and clip on cull tags if they must be used. I'd like to see them outlawed entirely. As many tournaments and clubs and circuits and people on the water these days with thousand dollar fish finders, we need to put more of an emphasis on making sure a nice 5lb bass can be caught a year later by somebody else.