With apologies to Gness for nicking her idea....
A foursome on the next table to us in a bar in Leeds ordering a £65 bottle of fizz and being brought a £200 bottle of Poll Roger by mistake which they let them keep!
Bliss by association.
A couple of years ago I ordered a bottle of Meursault at £57, which never got put on my bill. I told the waitress the next time I went and she said "I won't tell if you don't."
The restaurant ended up going bust funnily enough.
I just go into Italian restaurants with my friend Maura, for some reason older Italian blokes are all over her like a rash, we have had wine upgrades, free desserts, liqueurs, and on one occasion a more interesting offer including both of us, funny how he waited til she had gone to the loo before asking me if we would be interested.