I can understand why they wouldn't allow it.
If you think about it, in SchH, when they're running the blinds, when they find the helper, they have to aggressively bark/hold the helper in place, and if he makes an advance, they bite. (From my understanding, anyway).
I can see why SAR people wouldn't want this type of dog out looking for someone. Imagine that in a real life situation. SAR dog finds the person they're looking for, and the SchH training takes over their brain. They start the bark/hold, and if the person moves forward, the dog bites.... Obviously not every dog would do this, but I can definitely see the liability issue there.
Ozzy - Chocolate Pom
-Fastest 2012/2013 U-FLI Pomeranian
"In a perfect world, every dog would have a home and every home would have a dog."