WAYNE, N.J. - A New Jersey diner is adding an 18 percent gratuity to the bills of children who go there without their parents.

Melissa Desch tells WCBS-TV she and her family have been eating at the Wayne Hills Diner and Restaurant for years, and she was surprised when her 11-year-old daughter sent her a photo showing a 90-cent tip was unknowingly added to her milkshake bill.

Desch doesn't think it's fair to treat minors different than adults.

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The diner's lawyer said kids have been showing up in groups of 20 or 30, staying for an hour or two, but most don't leave a tip. He says it's not fair to the waiters and waitresses.

He also said the menu clearly states "management reserves the right to add 18 percent gratuity."

Adding a mandatory tip to kids' tabs is yet another wrinkle in the ongoing and expanding debate about tipping. For instance, some West Coast restaurants are now have two lines for adding gratuities: one for the server and one for the chef.