When the player is wearing a disguise, the hidden icon comes up. However, the player isn't hidden, just disguised to fool some NPCs. This is going to be very confusing to the new player who will think he or she is actually hidden and will be seen committing any crime he or she commits. ZOS really should come up with something different to show the player when he or she is wearing a disguise.

I had this happen while running a quest on Stros M'Kai, the spearhead quest where you have to get a servants uniform. I forgot about that difference, stole something out of a nightstand and of course got a bounty. I then progressed the quest, went out the back door to get Bosek's key. Immediately got confronted by the guard. When the confrontation was over, not only were my stolen goods gone, so was the costume. ZOS needs to make sure that all disguises are not marked as stolen.

This broke the quest because I still needed that costume to complete it. I had to abandon and restart it.