I am with Anatole and Jolly. If I was already in the car, I would have showed up just to make the birthday child's day feel a little special, especially if no one showed up. A couple of tricks, a few smiles and laughs, and on my way.

And as Jolly, I don't take a deposit.

This kind of happened to me Two years ago although I hadn't left our house yet. The party was local and was to take place in Two hours time. The Mum had only booked me a week before and there were only about 5 other children going. For some reason, they all cancelled on the day. I decided to just do it anyway and performed a few close up bits and bobs for the child and his family for about 20 minutes. I hadn't taken a deposit as I don't tend to for Children's Parties. Rightly or wrongly, I also didn't take a fee on the day, just putting it down to free marketing. The Mother phoned me up the next day thanking me for going ahead and filled me in on a bit of background. The child had started a new school and was having problems making friends. It would appear that his choice of friends stitched him up on the day. A pity.

I never got the return gig the next year but I do sometimes wonder if the young boy had settled in.

Rjenkins,

For the professional or not, I would have gone ahead and done the show and not charged a thing.
The whole purpose, or should be, is to bring joy and wonder into peoples lives-kids especially.
If you're one of those folks who only does magic for money, then why do it? It should never be
about the money, it should be about being a positive role model and influence for kids, give them
something to dream about. As a performer, you never know what kind of environment or situation children
come from; it's part of our job to take their mind off of that for a while.
Besides, that family may have connections to others and if you would
have done a free show, it may lead to a very large paid show. Word of mouth is free and it's the
strongest type of marketing out there-fancy website, business cards or not, if your attitude doesn't reflect
the art, then you have no business doing it.
Just my opinion.

Unless the client says not to come, I would do the show. I was asked to perform and I will.

The kid and family would have a much better day because of it. And so would I.

John

One day I got a phone call from the agent of a famous rock/country singer asking if I was available to do a show that afternoon at a party for the singer, who was a big fan of magic and in town for a concert. They had gotten my name by calling the local magic shop and the owner of the shop had recommended me. I quoted my fee--which really wasn't that outrageous--and they said fine and told me the time and location. I loaded my car and headed for the hotel. When I got there I found the person in charge, and he turned to his team and said, "Didn't anyone call Mr. Narvaez and tell him we found someone else at a better price?" No one had. They offered me free tickets to the show, but I was so angry that I said, "No thank you." I turned around and left. I knew the magician they had booked and I was sure he did a great job and there were no hard feelings between him and me when we talked about the incident later. But I thought it was very unprofessional--not to mention cheap--of the singer's team.

----- Amado "Sonny" Narvaez

Anatole, name and shame the cheapskate.

That would have left me furious too.

OP wrote: "I could tell from the phone call and looking at Google Street View that this was not a well-off family."
Using the Google Street View is a very interesting approach, I reckon, to vetting the "scene". Anybody else use this approach?
I considered contacting a school to see about busking at their coming event, but when I went to their internet site and saw from their publicity photos of the previous year the paucity of folks at the various events they showed I figured there weren't enough people around at the event to make it worthwhile even asking to be there.

I agree with Anatole.

As a general rule, I wouldn't accept last minute bookings for birthday parties unless I already knew the people involved.