MLB Umpire without mask during IBB?

[LMan]

Saw this on SportsCenter and wanted to ask the cognosceti here....

During a MLB game (I *think* this was the Cards game the other day where Tony LaRussa was banged out for arguing balls/strikes, but not sure), I watched a pitcher giving an intentional pass to a batter, tossing the four balls to the catcher...but during this entire sequence, the PU was standing upright behind the catchers box, with his mask off, holding it in his left hand down by his waist. He was idly watching the pitcher, looking bored.

Is this right? The pitcher is throwing a live ball, although I guess the bases were empty (camera didnt show that). Plus, even a soft intention-walk pitch is hard enough to hurt you if you take it off your unprotected face. Thoughts?

I guess my bigger question is, is there a 'mechanic' for observing/'managing' an IBB?