So my wife and the restaurant owner seemed to have forgotten the whole situation with the bill for the company party. But I guess that American Express decide NOT to forget it and reminded both parties that the charge was still open.

I have to say this is an example of time heals all wounds because my wife seems to be willing to pay most of the bill with only a minor discount. I think the owners is going to be very surprised.

What can I say, getting in the middle of the situation and not letting it get out of hand was the best thing to do. Whether your are a consumer or a business the longer you let things fester the worse its going to get. In business, you need to have a process in place, so at a minimum calms people down. In this situation not asking for payment working to the business' advantage.