I've seen those too. They're quite inconvenient because they actively prevent you from charging your phone or laptop while out of the room. They should leave some marked outlets enabled but usually they only do so for the mini-fridge. And of course "fancy" places build that into a cabinet.
I usually have someone's business card on me, so I'll stick that in the card slot so that I can head to dinner while stuff recharges or the room cools down (for places where the A/C is tied to the same switch). I have yet to see one that's anything more than a simple mechanical switch.
The one I ran into that did that had an outlet that would work when out of the room... in the bathroom, for a rechargeable shaver, presumably. So my laptop got plugged in there...
