Hi Mark:

The weight of that "unearned gain" on your conscience will follow you (and only you) as a stain on your reputation. I know it isn't much and the lady will probably never know... but what if she does? If you return the $50 bucks, think of the PR it will gain you for next year's gig... and she will probably tell ten friends about your honesty and talent.

Usually, what goes 'round, comes back around... and think how good you'll feel.

All the best,

Dave Rice