William - my understanding from other threads is that SNA's are automatedly applied by SPG (not the property) in a sweep starting 5 days out and that the sweep looks for availability (any availability?) in that room class and then automatically honors the SNA if that availability exists, and that it does that repeatedly until 24 hours before arrival.

Is this accurate, and if so, are there limitations on the availability of that class of room?

I'm sure lots of folks (not just me) would appreciate the clarification - thanks.