I have to say I didn't know about this but I suspected whenever I see the service charge on a bill that the wait staff does not get it so we have always left a tip for the waiter/waitress.  But after reading this I will slip it to them personnally.  I would hate to think the money we leave on the table does not go to the waiter but the manager. 

Seeing that service charge on the bill though, especially if the bill is from an expensive restaurant can be a surprise and a detriment to patrons leaving a tip for the wait staff.