The best that can be done is wiping the devices (factory reset), even Linux can be wiped with a live usb and dd!
the devices can even be sold (which might be less suspicious than just resetting.... one can false flag and claim to want to gamble but stopped themselves)
however, other false flags can be used too, for example the ppeh or other CTB manual can be downloaded after factory reset to disguise the source of CTB information, and kept on only 1 device not sold.
If I encountered something similar after someone I knew CTB'd, I would have completely fallen for it.