Nothing annoys me more, yet falls just short of risking an argument with the waitstaff.

I will use a Restaurant.com certificate, or an Entertainment book coupon, and they will calculate tax on the pre-discount amount. Then, they will add tax and mandatory tip on the pre-discounted amount plus tax!

Difference is about $5. Now I know that tax doesn't apply to coupon's, except when they are being reimbursed by a manufacturer. We know that Restaurant.com and Entertainment arnt' reimbursing restaurants for the coupons/certificates.

Has anyone ever challenged a restaurant on this shady practice?