I can understand an unforseen problem once in a while and for these occasions some loaned gear is a godsend. I've even been bailed out a few times myself. But I learn from these times and work to correct it by taking mental notes and addressing the problems. I never want to become "one of those guys".
On the same note, how does it become my responsibility to always have to bring extra gear for someone who is a chronic walking gear problem waiting to happen?
Same with lunches. I used to dive with a guy who would bring another guy (without me knowing about it before hand) and inevitably this other guy would show up hung over with no breakfast in him and he would bring nothing to eat during the day. Well common decency says that when you break out lunch and the other guy is looking at you starving it's pretty hard not to offer him part of your lunch. But where was his thinking?
We were going to be out there all day and the dude brings nothing, and he knew that.
So then he does one dive then sits up on the boat freezing his ass off because he has no calories in him and so our day gets cut short due to this guy.
I'm going to say for me it's three times. The first time it's completely forgiven, stuff happens. A second time, well maybe it was a freak. The third time that's it, see ya.