I have spent a few hours over the last few weeks trying to find the proper rules. I did find the 69 page manual for the temporary importation of: Vehicles, Casa Rodantes, Motorhomes, boats and motorcycles. I can understand what has happened. This manual shows the rules for what we call an RV as being different than a car or truck. There is reference to Sonora Only but nothing for the no hassle zone. I wonder if the manual for the No Hassle Zone does not reference Motorhomes. Just cars, trucks and probably motorcycles. Perhaps the Aduana is interpreting this to mean that RV's must get a permit. It is also possible that since I purchased my TIP a few years back at the insistence of the Aduana they are no longer requiring the permit. I will try to find the answer at Nogales. Here is a link to the manual:
http://www.sat.gob.mx/informacion_fiscal/normatividad/Documents/manual_importacion_vehiculos.pdf
Russ: Please do not call my post a rumor. I would like to know if I am right or wrong. I would prefer to be wrong and not have to pay for a permit! If it is required I would think that most would want to comply to avoid problems.
Moisheh