Did I misread the OP. I thought the only children invited were the couple's grandchildren.
I have been to numerous events where the only children invited were close relatives of the host. I have never been insulted because they my kids weren't invited.
In one of her responses she says it is only 1 family that has any kids that would be invited. That is why I said knowing family dynamics they are going to be insulted big time since they are the only ones with kids.
I wouldn't cause family issues over a couple kids. I"d just put them way in the back near the bathrooms