I used the become ethereal shout to become a ghost so I could run through some spinning blades in a Dwemer ruin, but as the blades touched me I still contracted "rockjoint" WTH? I guess its only useful for jumping off cliffs. --- Retrouprising.com - Just about the best video game site ever made!
Traps set diseases despite immunity/ethereal. Even werewolves and vampires can contract diseases from traps.
You can even contract Sanguine Vampiris. Unfortunately the diseases set on the traps seem to be random. --- Testing: Werewolf/Follower Glitch; Armor usable with Mage Armor and hidden +25 armor/pc; Augment Ring of Necromancy