Don't know if I buy in to RF being the biggest source of false triggers from motion detectors. I think it would have to be a very strong signal at close range to the detector.
FWIW
This would be easy to test if you have a couple of the little FRS radios. They put out an ERP of less than 500mW. Sneak up behind your MS10 while keying and unkeying your radio. How close do you have to get before the MS10 transmits a detect signal when you key your radio? My bet is; IF the MS10 falses it won't be until you are within inches of the unit. Since RF attenuates from the source at an exponential rate, even high power transmitters would have to be fairly close to the MS10 to false it. Any neighbors who are Hams?
As Brian H pointed out, RF shielding on an enclosed antenna wireless unit, pretty much defeats the point.