My FH and I purposely did not give his brother slots for his kids. His brother said something to FMIL about it. FMIL told him to cross the 2 out for him and his wife and put 5. Which all of this was told my FH over the phone by his mother. My jaw dropped that this would be suggested. I had seen this mentioned on these boards but never thought I'd ever hear of it from his family. I told FH that that is rude and hope his brother doesn't do that. I also laughed because I'd seen this on the board and was in awe of the suggestion of his mom.
He messaged his bro the other day about it and is still waiting to hear from him about what he's planning to do about the kids. He really wants his bro there and is willing budge on the kids if necessary. It's not the end of the world if they come, but I'll hold a grudge if the kids do something during the ceremony like scream during vows because they're toddlers/babies.