It all comes down to repecting the person and their property. I hunt my wifes, cousins property and we have agreed we don't shoot anything smaller than what is on the wall now. For me that is 120". I had a nice 8 pt last year walk within a few yds and was a chip shot but he wouldn't clear the 120 because he had no mass. I passed on 4 bucks that same morning. Later in Rifle season him and his wife both shoot small bucks. I wasn't to happy to hear that because of our agreement and I clearly passed on the better buck BUT, it's his property and his rules and he can change them at anytime. I respect him and i'm lucky to hunt this place and I will continue to follow our agreement on my end and not use an excuse of "well you shot 2 small ones last year." I remembered what i said and therefor I will follow that.
Next, i'm going hunting with a good friend on his property this Sat. to get a few does. There are some really big bucks there and bigger than what I'm hunting now and he has simply requested that I only shoot does. I'm fine with this. I'm not going there to shoot a big buck, I'm going there to enjoy some hunting with a good friend and film. In the heat of the moment I could easily let one fly on a biggin and play the card "oh man, I just couldn't pass that one up..sorry" but since I RESPECT my friend and his property i would never do such a thing. I would give your buddy another chance but clearly explain the expectations and let him know you both are guests on this land and need to respect the rules that have been set. Just because you're family doesn't mean you get an automatic bye to hunt there. When it comes down to it, you are responsible for who you bring onto the property with you.