Why sneak? Why not just fly in on a Yalm and flip the switch? Might as well not have guards if they terminate when the town/area switches sides as with that scheme it's ridiculously easy to take them out at any time. There needs to be something to force people to actually get threw some of the defenses rather then being able to completely bypass them.
The tactics could be awesome. A three pronged assault designed solely to get some Engi's in so they could beconwarp in some reinforcements, some snipers sneaking in to take up good fireing positions and all sorts of fun stuff, but being able to flip a switch and instantly take out the guards negates the need for any real tactics.