The old ones (never seen the tip option on those... for now): https://www.simple-shop.si/en/pos-terminal-tcpip-en and eg https://www.unicreditbank.si/si/podjetja/upravljanje-z-denar...
The new ones: https://www.sumup.com/sl-si/karticni-citalec-terminal/ and https://besteron.com/si/pos-terminali/ (both support tips) + many other in similar designs (full front touchscreen)
I don't think square supports slovenia for now, but POS vedors add the tip option, and our restaurant owners enable it, because it doesn't cost them anything, any many (especially foreign) guests "feel bad" for choosing the zero on the screen.
At this point I'm waiting for supermarket self-checkout to add a default tip amount.
Esso petrol stations routinely ask for this, and the staff member ALWAYS clicks the 'no' button before you can offer your card.
Source: Somebody who drives around the UK a lot for work.
But obviously, a government service should give fair and proper service to everyone.
It's also more money to the company providing the payment system so they are incentivized to tell every restaurant to turn on tips.
I hate it. I don't know how to fight it except to try to start a movement big enough that everyone who goes to such a restaurant gives it 1 star and not not return, until it becomes unacceptable for business to do it. Like many things that is unlikely to happen without some major awareness campaign.