I think even though Pauls place is a respectful employer there are far more on the grand scale that don't pay it. And the further away you get from money the less likely you are to encounter the obligatory service charges. So I think it is abused, yes, and money not placed in cash directly with the waiter often goes into the owners payroll account and saves him money.
I've said before that if I see this sevice charge is obligatory I try not to eat there. Obligatory service charge is ridiculous, that is his job, and that charge is his wage, to serve you otherwise what is he doing? It is then down to us to choose if the service was exceptional and worthy of a tip.
In making it obligatory our opinion on the service is already made up for us, by the employer, our opinion is void, which is shocking, hence my avoidance of anywhere who tells me what service I received before I even sat down (service charge).