If you had been invited to an (adult) family members birthday party by their partner with the following invitation:
"Would you like to come to xxx's Birthday party it's on XXX kids are welcome to come too"
We confirmed we would like to come and thanked for the invitation.
When they came to pay for the birthday party 2 weeks later would you expect to be asked to pay for your portion of the party and food? It's for an activity which will be pay per person not big hall (similar to a children's birthday party)
This has happened and I am surprised, it's enough money to have made me think twice about originally accepting the invite but am still happy to go now we have made plans as it's not local.
Maybe because i'm used to children's birthday parties which I would never ask my children's friends to pay for themselves after inviting them.