It's so legitimate that even my mom thinks it's a good reason. That might be due to the fact that she's not going, either. After all, Grandma's Little Angel (aka my nephew) has a football game that day.
We're (my mom, sister and I) not going to this baby shower because we weren't invited to my cousin and his now-pregnant wife's wedding. Quite honestly, I can't remember who it was that didn't want us there. He probably didn't, but I seem to recall hearing something about her family not wanting us there. Which is odd, because I have no idea who they are. My mom and her sister do not get along, but we went to the other two boys' weddings. I didn't pay much attention when it was all going down because, hey! I don't have to go to that wedding!
Look -- it's not like I would have gone to the wedding anyway. However, why bother inviting us to the baby shower, if we were not welcome at the wedding? I can count on one hand the number of times I've talked to this girl. In fact, I'm not even sure I was ever introduced to her. It was just one of those, "Hey, who is that person?" at Christmas one year. And then she kept showing up to shit on the rare occasions my loser, douchebag, delinquent cousin showed up to family functions. I probably wouldn't know who she was if I ran into here on the street somewhere.