Sure they can be used but the whole visual idea I got was pretty funny or so I thought anyways... Just think about quiet night with enemy guards waiting at their post. Everything is quiet. Suddenly they can hear sound
SQUEEIIIIKKKKKK
SQUEEIIIIKKKKKK
SQUEEIIIIKKKKKK
SQUEEIIIIKKKKKK
taptaptaptaptaptap
from the silence of jungle/desert/city streets
guard 1 : "WTF?"
guard 2 : "Oh, it's just those stealth robomules they use"
guard 1 : "Stealth robomules?"
guard 2 : "Yep... Normally we just run and chase them down and if they are carrying patient we take him as POW and if it's supplies we rob them. Sometimes we just toss them grenades and watch it dance with three legs or start running in circles. Lots of fun, you know?"
guard 1 : "What we are waiting for?"
I know that those things could be priceless when it comes to passing deliveries trough minefields or scouting in such areas but nonetheless I find them pretty funny. Hell, maybe they even load them with bombs and make suicidebomber-mules, kind of like missile with legs. Who knows what those warped minded weapon engineers come up with. Like those suicide bats of WW2 that they tried to make carry tiny ignition bombs with them to Japanese homes and stuff like that.
EDIT : Ok, maybe that would mean that I would laugh at wrong place and get myself shot full of 5,56 mm holes. It's very good to know when you have to keep up your appearances... In battlefield and like, when being talk show host.
http://www.youtube.com/watch?v=kXf3wx5nPXU