Hola, the foam plates work only in the states of Jalisco and Nayarit (PV). they should not be used to drive to ZLO or Manzanillo.
I have used the plates. One time even, along with a letter from La Huerta President requesting safe passage, I went to a town in Colima to pick-up and deliver a rink in my big u-haul. No problem even when stopped at the miliary checkpoint by soldiers before crossing the bridge into Cihuatlan. I did not even have to show my letter as they only checked my load.
So, as far as I can see, the plates have respect. And if you are stopped and questioned, which suppoedly is rare, you call Onnappafa. And as we know, in Mexico anything can happen.
Onnappafa's claim to fame is that they are a very large group with some clout. they only exist and work in these two states so as not to spread themselves too thin.
One thing I do say is that I only own clunkers. Cruz