I feel like it all depends on if the Spartans have an AI with them. Ghost (being essentially a snarky floating ball) can't even stand up to Rasputin, where as cortana (a snarky purple chick that actually does some useful junk and helps progress the plot) hacked a damn halo (which was made by an advanced alien race). Given the most guardian armor seems to incorporate some form of technology to boost a guardian's abilities, I feel like an AI could just hack it and order the glimmer composing the armor to disintegrate or something. Meh