Quoted from inhomearcades:

Exactly what helicopter said. It's ebay. Nothing is sold until cash exchanges hands and the machine is loaded up.
As for having a tech come with, I wouldn't care if he brought a van full of people to check it out. Why in the world does it matter if the buyer does not have the ability to check the game out himself? If he said the game is working then he has nothing to worry about. If he is concerned the buyer will want to renegotiate the price after he inspects all the seller has to say is no. It is very irritating that there is anyone out there that sides with the seller in this instance.
There really is not a debate to be had here. A buyer has the right to try something before he purchase it, if not then just as in this situation, it's not going to be sold.
Also the price of the machine is irrelevant, why is it that every thread turns into a pricing discussion? It doesn't matter if this Twister was 10k or 100.