I think you need to negotiate this in advance as part of your banquet contract. I just planned a family reunion at a Hilton-family property and brought up the subject of points credit after i signed the contract. My guy said it needed to be part of the contract. He offered to give me 750 points. Whoopee!

I did put the the cost of the banquet on my Hilton AMEX card and got 5 points for each dollar spent. So it worked out okay. I ended up with about 15,000 points for our $3,000 banquet.