Doug,
yes, big antenna masts can interfere with the datatool's remote frequency. I have a buddy of mine living near a big public television/radio network antenna mast and sure thing. pushing the remote wouldn't work, not even holding the remote against the alarm unit.
So, adding a switch beats the purpose of an alarm somehow, and IMHO would not be a good idea.
There is always the manual override mechanism via the key:
* initiate the alarm by switching the engine on - let the alarm go through the alarm cycle -use ear plugs

* When the alarm stops you have 5 seconds to initiate the key override by turning ignition off and on again. Then count the beeps until first number matches then switch off, etc. for the other numbers.
* if this happens again, move the bike behind an obstacle big enough that you don't have a line of sight with the antenna and preferably in metal (Faraday)
* when I park the bike, I check if i can see any big antennas, if I do, after switching off the engine, I try immediately to set the alarm, if the remote fails, I restart the engine I seek out another spot to park.. without pushing

hope this helps