Youtuber LockPickingLawyer provides a dramatic video demonstration (embedded below the fold) of the dangers of gallium contamination to aluminum: A small amount of body-temperature-melted gallium placed on the scratched surface of a solid aluminum lock body will render it breakable by hand.
I previously covered gallium rot and the dangers it poses to AFDB-users on this blog over a decade ago, so this should not be news to any informed paranoid. But take this as your decennial reminder to keep gallium away from your psychotronic deflection tech. If it can do this much damage to thick cast-aluminum in only a few hours, imagine how quickly it will eat away the foil layers of your beanie!
Aluminum-lined bunkers are not safe either if attackers can find openings to drizzle in gallium, so remember to inspect your bunker walls for cracks and gaps and seal them with silicone caulk.
As LPL points out in the video, contamination by hand could spread the gallium rot to other aluminum items. Don't let anyone touch your AFDB as their fingers might be coated with gallium residue.
While aluminum's naturally forming oxide surface should protect you from sudden beanie disintegration, any scratches or mechanical stress fractures that occur after contamination could let the residue seep in. For added protection against the gallium-grubbied paws of mind control agents, consider spraying your beanie with latex paint.