In the UK, where minimum wage is OK (not great, but OK), and we don’t have those garbage US shenanigans where tipped employees can get paid a pittance, many payment terminals add a 10% tip automatically (especially at bars). Many restaurants also add a 10% tip to the bill (For everyone, not just parties of > 6).
I really wish it were outlawed. The price paid should be the price displayed, unless the circumstances are exceptional. You cannot display prices without VAT so how it is allowed to display prices without the forced tip?
“It’s optional”. Sure, if you enjoy having your food spat in the next time you return.