Quick Ethical Question

If you receive a BrickLink order that's missing a few parts, but also has extra parts that are more expensive than the missing parts, do you tell the seller? Also, what do you tell the seller?

I'm considering just leaving glowing feedback without mentioning it - in the end, he's out less than a dollar because of the mistake. The missing parts were just parts I wanted to have on hand and not something I needed for a particular project.

Additionally, the guy's already out a couple of bucks because shipping was more expensive than expected. Working out additional shipping in either direction doesn't seem worth the effort (ironically, if not for the last time I moved cross-country, I'd probably have met the seller in person by now).

EDIT: I decided to just leave good feedback and not bring it up.