We had invited 8 kids to the party, had just one RSVP ... not a good sign, to be sure ... but we expected that SOME more folks would show. As it was we had Daughter #1, Daughter #2, and Daughter #1's "boyfriend" in attendance. NONE of the other kids even responded.
The boy's dad did suggest that this MIGHT be a "plan" by Daughter #1 (i.e., to have 1-on-1 playtime with him), but I just can't see her ditching the other invitations and just handing out that one! She's too into "loot" for that.
Fortunately, she wasn't too upset (we had to pay for a minimum of attendees, plus had bought other tokens, so she was able to go WILD with the machines) and seemed to have a good time. I would have been CRUSHED were it my party.