I've been here for almost 11 years and have never turned someone in for anything. That does NOT mean that I won't. I see rules being broken all the time, and it doesn't get reported, but there is a line. An example would be drinking on the job. I will not tolerate it and WILL turn someone in for that. I know that's kind of a crappy opinion to some, but that's the way I am.
I want to know what the writeup was for. A West FA snitched on you. OK. Did you steal a can of Coke (as was offered as an example earlier)? If so I'm with you 110% that it was BS. Did you miss a latch on a galley cart? I'd be with you there too. But if it was something more serious like drinking, well, you deserve it. You can't (well you CAN, but you know what I mean) come in here, say someone snitched on you and they're evil because of it without putting it in perspective. Don't cherry pick facts, give the whole story or none.