I think the issue with the reselling/renting is that you obviously cannot sell a fake or invalid ticket. You can put a ticket to a concert up on Stubhub but the expectation is that it's real: if it's fake you're guilty of fraud.
There's no way to sell a valid multi day ticket that has already been used at least once. Disney policy is that tickets are non transferable whether money changes hands, and that trying to use someone else's ticket renders it void. There's no way the resellers can't know about this condition of sale because it's all over the ticket.
These sellers are therefore trying to sell invalid tickets, and that is illegal.
With IDs, again, not everyone has a valid state or school issued ID. A lot of guests, particularly from out of town, are little kids. A lot of school districts don't issue IDs until high school. I went to school in a major city and until I was in 9th grade I didn't have ID. That school ID wasn't legal identification, either.