So my FI has a group of friends that he has known since college and has spent his 20's and early 30's drinking in bars with. One of these friends is getting married and FI is invited to an OOT bachelor party next month. Because we have so much going on this spring/summer, I asked him to find out when the wedding is, so that I could add it to my calendar and plan around it. He said that we shouldn't count on being invited to the wedding because it's pretty common for these guys to invite guys who aren't invited to the wedding to the bachelor party. He then noted that he will probably do the same thing for his bachelor party because we won't be able to invite the entire 15/20+ group of guys to our wedding.
Of course that sets of my etiquette alarm and I immediately said "you can't do that!". I know that guys are dumb about these things, but do I really need to put up a fight with him about this or should I just let it go? On the one hand, FI has noted that he is really happy that I am ensuring that our wedding is going by the book etiquette-wise so that we aren't upsetting people. On the otherhand, its a bunch of guys and it's just an excuse to drink and hang out for them. They don't get pissed off about that kind of thing-at least that is what FI says. What would you do?