Real world advice

If you get caught you won' be allowed back into the Schengen area for a very long time, if you get caught then other countries will notice the big stamp in your passport and will refuse you entry on the theory "once a crook, always a crook". If you are involved in an accident or require medical assistance then your insurance company will almost certainly refuse to pay out. If you are involved in an accident any insurance you have is invalid therefore you are committing a criminal offence