I'm thinking it would work like this:
Muscle: Shut yah eyes! If I see 'em open on the way to HQ yah dead!
Player: Ok, sure, anything just don't kill me!
Mugger sees: player covers their eyes in fear, they won't see a thing till they open them.
The player can then @blindfold me again to open them up, with a message displayed to those watching them. Ideally you'd still hear things as you would when in a pitch black room. Seems like fun RP. The person could try to sneak a peek if they wanted, and the mugger would have reason to end them if they got caught.