as seen here: This description was written pre-Encrusting. I think it may have prophesied it. Now that it is possible to strap things to your armor I think it's mandatory.
Ever heard of poisondart frogs? Mean little beasts in many colours, touching them causes you to be poisoned pretty badly. That's what it's referring to. Edit: Aegho, stop ninja'ing me.
Ah, now I recall encountering some really tiny frogs when camping a long time ago. Everyone thought they were so cute and were petting the little creatures until they got scared and started peeing on people. This defense mechanism 'encrusted' people with a horrible smell that would only go away after much sweating. Those were not poison-dart frogs but the smell was rotten. Maybe there's an idea there?