I invited parents, siblings and my daughter's friends to her 4th birthday party last week. Most parents were very good about replying. All they needed to do was a quick phone call or mention it to me at school or something.
I was rather put out to not hear from one mother at all, then on the day of the party, she sent her helper with her daughter (no, she doesn't work). Daughter behaved badly at the party and the helper was totally ineffective.
I didn't even know the parents, my daughter just liked her daughter and asked me if we could invite her. NEVER AGAIN ! Rude woman, spoilt brat daughter, not coming to our house again.