As having recently realized I could easily do this (get 6 fast passes per day) (And being able to do it at 30 days out because I still have an active (non-expiration) ticket on my current
MDE account).
I'll be honest, even though it is "gaming" the system, if I am going to book another trip, I will be tempted to make a new MDE account to do that (especially for MK).
But, if 10% of the people in the park are using two sets of bands, that is like having 10% more people in the park (for wait times, not "congestion").
It's a loophole I am surprised they haven't closed (and I would expect them TO close it eventually).