Your best bet is to get hold of the NCTI Installers course, it will give you the basic"s of a cable system and how it works. When you get the chance talk with the Maintenance guys or the service tech's.
As for your question is a cable system that fragile that one A/O can mess up a whole system. The answer is yes if there is enough noise/ingress on it. That's one of the main reasons for doing a install correctly. Hell a loose F connector at a tap can let in enough noise to take down a whole node. The same F connector can let enough signal leak to fail the FCC's CLI specks.
Now brace yourself for all the comments on your questions, I could think of a 1000 smart-ass reply's I could post to your questions but I'm in a good mood today.
