Throwing a party and informing all your guests that it is ‘adults only’ because you don't want kids to attend, is completely fair and up to you. It is also completely fair and up to your guests to refuse the invitation, especially if they have kids who are forbidden from attending the party. If you cannot understand that a rule like that would minimize your guest list, then maybe you should reconsider the rule. That is what I would have said to the brother in this Reddit story, who got upset wi…