Dive-aholic:I agree, just because the line is there doesn't mean it can be trusted. You have to learn it first. My point was that I've heard of caves in Mexico where you'll come up to a "T" that branches off in 5 different directions. Mark it, swim on, and come across another "T" that branches in 6 different directions. That's a little different than what's found in Florida, and I don't think those extra Ts were laid by Florida divers (although I could be wrong on that). I've had limited experience in cave diving so far, but what I've seen and heard is that most of those "T"s would be jumps or gaps in Florida, not tied directly to the gold line like in Mexico. It could be dived safely, but it could become very confusing too.
You're right in that now days jumps would be prefered. That mine in Missouri that I mentioned had a real mess in it and a few divers have been gradually replacing it. I think the guy who did the original UW explaoration was a "Florida" cave diver though. It's just more convenient sometimes to just tie off and go especially when you're not laying the line with tourists in mind. Whether in Mexico or elsewhere, I think you can expect that lines in caves off the beaten path to be layed in a less "refined" manor. From what I've heard that is indeed the case in Mexico. Still trained cave divers should have been taught to cope...when in doubt, tie off, place a marker or whatever.
When my wife and I first started diving mine Lamotte we went very slow. We limited the number of intersections that we passed and at each intersection we each placed our own marker. The vis can also be bad and the water is COLD. There's no doubt that you have to keep your mind on what you're doing and think about how you're going to get out before thinking of how you're going to get further in.