I don't know, I've never heard of that happening to anyone.
But a quick google says if that were to happen to you it's best to just leave it and wait for the owner to come back, it's not illegal(it's only a civil offence so you'd need to sue the person who did it), if you get it towed you have to pay for the tow and you'd be responsible for any damages that happen to the car in that time.
Again, that sounds purely theoretical, I can't imagine it's actually common.
Depends on the city for how harshly it's enforced on public roads, but you absolutely can be towed off private property pretty much anywhere.
Check out GToger (sp?) on YouTube. IT guy who was working in Dallas (hasn't posted in a long while, maybe changed jobs?) in an area heavy with nightlife. Tons of videos from surveillance cameras of people getting towed for parking in very clearly marked "NO PARKING" spots.
But a quick google says if that were to happen to you it's best to just leave it and wait for the owner to come back, it's not illegal(it's only a civil offence so you'd need to sue the person who did it), if you get it towed you have to pay for the tow and you'd be responsible for any damages that happen to the car in that time.
Again, that sounds purely theoretical, I can't imagine it's actually common.
Is that a common issue in the US?