The door chain one makes sense only if you can open the door from the outside, but only partially because of the chain. You could then reach through with your hands to connect the rubber band while standing outside.
When might this happen? Not often. Maybe if your partner locks you out of the house, or if you locked the front door and then went out a back door. Or perhaps you come home and someone inside is incapacitated and you need to get in.
The acne thing might have something to do with absorbing oils from the facial skin.
The skull remote trick isn’t amplification, it’s parabolic focusing. The drawing is confusing because it shows the waves emanating in the wrong direction I think. Tilt your head back so that the bottom of your jaw is pointing in the direction of the garage/gate/or whatever. At this point the inside of your skull also points in that same direction, and will serve as a parabolic mirror for the infrared or radio waves (presumably. I’ve not tested this). Then place the remote under your chin, pointing at the bottom of your jaw, and hence also at the inner side of the top of your skull. The hack claims this will then reflect that signal in concentrated form in the desired direction.
I thought the obvious choice was the beer taster one, since it’s a complete lie (explicitly admitted). Or are we supposed to find one other than the beer taster game controller trick?