A friend of mine knows someone who was working illegally in a pub in England. He left the country somewhat frequently to visit his girlfriend, and after a while the authorities at the airport started to question him about how he was affording all of that travel. They searched his bag and found pay stubs from the pub. He was allowed to stay in England for another two weeks, but he now has a stamp in his passport that says he is not allowed back into the country (which makes him hesitant to go to other countries for fear they’ll start asking him about what happened).

I know that was a rare case because he was doing all of that travelling, but do be careful if you plan to work illegally. It would SUCK to get booted out of a country.