Finally - A 1963-D Kennedy Half!

(Almost) all of his overstrikes use an original piece matching his new design -- these Ikes are done over genuine Ikes, same for his Peace dollars, Kennedy halves... He's done some alternate designs on genuine pieces, like this concept dollar below on a genuine Presidential dollar (how they know it was Garfield, I have no idea).

As for the legal issue, there's arguably no intent to defraud because none of his pieces can be presumed to be genuine -- the dates do not exist (e.g. there are no genuine 1975 Ikes). Some people argue that he's destroying genuine coins to make these, but he's generally taking "junk" coins with marginal market value as they are, so there is relatively little lost.