I've recently returned to the UK after a long stint down under, and the 12.5% 'optional' service charge seems everywhere I have been or am going to.
What's the rationale for it? Why 12.5%? And why is it said to be optional? - if I get served, I really have to pay it. No-one describes their food prices as optional, but if I have a crap piece of meat I won't pay for that either.
I realise this is turning into a bit of a rant, but I really would be grateful if someone could illuminate me as to where it all came from and when it started.