No, not that kind of trick.
Have you heard about it? Supposedly, when you check in to a Vega$ hotel
- you present your credit card wrapped in a twenty;
- you then ask if there are upgrades available;
- if there are, you get the upgrade and the clerk will keep the twenty;
- if not, you get your twenty back.
Apparently, it also works for car rental upgrades.
If you try it, and it works, let me know in the comments.
There’s a FAQ too.