A few more...you're 1000 over gross and Captain does not care, RVR's 1400 and Captain says he's done it 100 times and wants to get home. What to do?

Hopefully they realize I've never been in the Part 121 environment and can't speak from experience on these things, but what are the ethical channels usually to go through in that situation? I'm guessing talk to the Captain, reiterate the importance of company procedures, try to consult some other crews to get another opinion, before moving up the ladder. What's the normal procedure for this sort of thing? And how come all of these captains keep breaking the rules?