Can say I've pretty much come across all of those.
At the end of the day, the buck stops with the PIC. Despite a bosses push to get you out there overweight, or in the **** weather, and its their AOC, wont stop some of them trying to get you to break the rules.
They know its not entirely their arse as they will turn around and say "we said give it a go if you think its ok, your in command its your decision" It will be a word against word battle, and you'll lose because you broke the rules.
Overweight:
"we've carried this load before. why cant you do it now?"
"its only a few kilos over, whats the big deal?"
Below minimums:
"others were/are out flying"
"its not that bad. weve flown in worse"
"they could make it in"
U/S:
"thats been broken for a while, hasnt been a problem yet though"
"its only minor. we'll get it fixed when you get back""
"the engineer said its ok"
Home Made approaches...
"the GPS will let you know when your over water, just let down there"
It goes on. Frequently enough to be of some concern, but not entirely an everyday expectation- not from what i've seen.