How vulnerable is an exposed USB port in an pharmacy, shop or bank?

So this is just a question that popped into my mind the other day, sorry if it doesn't fit the community.

At the local pharmacy I noticed two USB ports on the back of the monitors they were using and I was thinking I could've easily gotten a RAT in there if I was more smart and malicious.

Similar places were banks or shops, sometimes ethernet ports as well.

Realistically, how dangerous is this? Thanks for any answers.