It's not often I eat out but, a few weeks ago whilst visiting London, a few restaurants added an 'optional' service charge of about 10-15% to the bill!
When asking to pay, when they come back with the bill and the card-reader to take payment I imagine its few people who notice this and even fewer who challenge it and ask for it to be withdrawn for fear of 'causing a fuss'.
The cheek of it I tell thee :thumbd: