Microwave vent

I am installing a combo microwave/range vent. Is there any reason it can't vent into a garage?

 

OK, found it:

RANGE HOODS
M1502.1 General.

Range hoods shall discharge to the outdoors through a single-wall duct. The duct serving the hood shall have a smooth interior surface, shall be air tight and shall be equipped with a backdraft damper. Ducts serving range hoods shall not terminate in an attic or crawl space or areas inside the building.

Exception: Where installed in accordance with the manufacturer's installation instructions, and where mechanical or natural ventilation is otherwise provided, listed and labeled ductless range hoods shall not be required to discharge to the outdoors.

IMO the exception was pretty clearly intended to allow the "recirc" hoods that vent back into their immediate environment, I doubt any manufacturer's installation instructions will allow venting to a garage, for example Broan says:

“You should never exhaust air into spaces within walls, ceilings, attics, crawl spaces or garages. The humidity and grease collect in the space.”

http://www.broan.com/display/router.asp?docid=123