[whatdude]

Getting time off is all dependant on your branch, the staffing situation and when you are trying to take the day off. If you end up in a branch with a shitload of cars and few employees, it's gonna be hard to get time off. If you have a legit reason they'll probably work it out, but if you just wanna take a Friday off, good luck. As for being fired, if you request a day off, it gets denied and then you call that morning at 7:45 and tell them you're sick, then yeah you might have to face some consequences. But I've never heard of someone being fired for taking time off. That's not to say it's never happened, I just never encountered it while I was there.
On the other hand, if you are in a branch that's well staffed and organized, with a BM that has half a clue, you can get time off. You might have to compromise a little on when you get it, but you can get it. I know it's called choice time and ideally you'd be able to take it whenever you want, but it doesn't exactly work that way.
This is all assuming you're an MT or an MA though. BM's, as long as they have a capable Assistant and a reasonable ARM can usually take off when they want. Assistants on the other hand, get the shaft. Just my personal experience speaking here, but I found it was insanely harder to get time off as as AM then at any other level. You want to give your MT's and MA's breaks so they don't kill each other/customers/you, and your BM can pull seniority on you at any point. Again, if either of the branches I was at as an AM had adequate staff or solid BM's this could have been different, but it wasn't.