@Frank Apisa,
Let's say you're being less than direct. I think this is a peculiarly American problem, not to say that there aren't illegal workers over here. It's something the owner of business would be tempted by, but not someone looking to tarmac their drive.
Over here the ethical problem is, 'Through the books, or cash in hand?'
We have a lot of foreign legal workers, Poles being the most noticeable group, in Southampton at least. They've got a reputation for being cheap and reliable.