I haven't read of specific experiences, but it is strongly believed that this will NOT trigger the credit due to the part about charging to the room to obtain the credit. There may be DPs within the thread that confirm or refute this, however.
Cheers.
I don't know who strongly believes that (passive voice groan). I on the other hand *have* read of specific experiences. This has been discussed numerous times in this thread. (Posts 876, 948, etc.) If the hotel front desk charges it, there's no reason to believe there wouldn't be a credit. Amex doesn't get a break down of what kind of charges each item on a bill is. The problem is if a restaurant or spa actually has its own merchant account and processes the charge separately.
it is no different than the dozens of people who had the credit applied to charges they settled with the hotel when they used points to pay for the room.
If you can't take the time to read about people's experiences, please don't speculate and pronounce an authoritative baseless view.
Cheers.