In my opinion, if you paid to park at the Poly and you ate dinner there, you should be able to go where ever you want. You pay to park at the main lot for the same price so why should it be any different? I have self parked in the past and went to the MK. Now I know that they frown on that, but if it is a slow time of year and you patronize the hotel, you know shopping or eating, then I think you can sneak away to the MK for an hour or two. Who will know? If you want to be safe though pay for the valet. There shouldn't be any problem.