Most of it is black and white... but there is also some grey :-).
I guess it all depends on how the agreement with Hyatt is drawn and how it's booked in the Hyatt systems. Some of the 3rd party travel advisors seem to have a dedicated rate which they can book, not unlike a corporate rate.
The TA's that book block rates at a discount or get a cut from regular rates are the ones to be wary of when you want stay credit.