The old line was that you could only acquire a legitimate used license if it was obtained through the purchase of a business. Today, even having a license that they recognize as legitimate wouldnt get you anywhere upgrade wise if it was too far in arrears in maintenance.
As far as using an older version that is not pirated, ie; has a functional hardware lock. I think they would not be able to do anything to you. Finding a license like that is the hard part.