I recall reading stuff written by security experts about some tale-tale signs that they use to pick out the BG's. It seems one of the biggest ones was what they called "swivel-neck."
The problem with looking out for the 'swivel necked BG's' is not looking like a 'swivel necker' yourself.
We have a saying in the UK. 'Paranoia will destroya.', but that's always qualified with the 'it doesn't mean the 'B******s aren't still out there to get you'
Its a fine line.
I wouldn't really read to much into what a security expert says anyway. From their point of view a healthy fear of crime helps keep the crime and security industry profitable.
Paranoid tendencies aren't just a personal affliction it is a society one too.
We must always remember that the founder of 'Game theory', John Forbes Nash, the mathematician whose ideas were so beloved of the RAND Corporation was himself a paranoid schizophrenic.
The
Prisoners Dilemma is quite enlightning.