Potter i thought the term Crotch Goblin very apt and funny.
You might not be using it on MN but I will!!!
As a pp said, don't get censored by posters who "didn't get it".
It's so obviously not directed at the child, but a really rather apt description of parents who insist others fund their offspring.
I think we could now call them CFGC's 
OP - glad you're sticking to your guns.
I've been there re: a long weekend away with another family (they had 4 children, we had 2) who expected to split everything (meals/hotels/entertainment tickets) by household rather than by person. It would have cost us an extra £500....
DH and I just laughed and "pretended" they were joking as it was such a ludicrous idea.
The classic was they said "well that's how we did it with X other friends" and DH retorted "well that explains why they don't socialise with you any more" (we'd noticed the friendship had cooled but didn't know why and didn't pry - but all became clear)...