I had dinner with my family in Westin Market Street, San Francisco. We were total five persons.
When I received the check, I went it through as I allways do.
I noticed that there was service charge added in that check. The waiter did not mention anything about that.
In that same check there was a note that they will add service for parties of 6 or more. Also the gratuity column was open.
If the restaurant acts honestly they specially make note that tips are already added, not deny it. So they clearly trid to cheat us.

This is a clever trick since only few customers go through their checks and notice that the tips are unusually way already added.
Customers usually just add tips to subtotal and pay the check.
That way the waiter gets more that double the tips.
Does he share the extra with the management, I do not know.

Is this common nowadays?