Yes, they never charged my card before my stay. I printed out the text, canceled, made new res for the same rate but lower price, and again was never charged until check-out. So it was treated as a flexible reservation (in line with the cancellation policy), even though it was advertised as a prepaid reservation.

I had a quick word with the front desk agent and he said the text in the cancellation policy is the only thing that matters, not the title or how it is classified. Seems they have been misclassifying a lot of ex-SPG fares as "prepaid" or vice-versa. Obviously, I had the good scenario (advertised prepaid rate treated as flexible rate), I can imagine those in the bad scenario (advertised flexible rate treated as prepaid rate) are not going to be happy.