We are having an "adults only" reception except for the 4 children in the bridal party (my FI and I's nieces and nephew). The reception is a cocktail party, which I don't believe is really a place for kids anyway. I gave all single adults a +1, except for a cousin who is in college/ lives at home and does not have a boyfriend and her brother who is in highschool. I invited the highschool aged cousin even though he is not technically an adult because he is nearly 18 and I wanted him included. I got the response card back and the college-aged cousin is not attending because she is away for the summer, however, my aunt and uncle wrote in a "date" for my highschool aged cousin. I will probably let it fly, but I am still annoyed at this and feel it was pushy and out of line for them to do so. Am I being unreasonable?