It only takes one bad client to turn a WG onto drugs to numb the pain and the punter doesn't even have to be that much of a cunt to do it.
Security buddy or not, certain types of people will kick off no matter what and some even get off on the additional drama witnesses may bring. Kinda like how CCTV only stops the people who were never going to rob you anyway, but now people either don't care about being seen or worse, play up to it.
Most knuckle draggers will only say, shout or scream nasty things but even if they do get physically abusive, the damage could be done long before help arrives, if at all. Fortunately they are unlikely to be as callous as to twist someone's head off in the blink of an eye, preferring to bludgeon, scratch or strangle instead.
The job comes with risks and a WG should know, accept and make attempts to minimise those risks, but unless they like the cock and they are so good at it they shouldn't do it for free, they will be better served out of harms way. On a long enough timeline something bad is bound to happen eventually.
If you don't ever want to see a WG on drugs, don't be a as much of a cunt to send them there in the first place. But if you do find a WG is on drugs and there are some obvious problems because of it, it might not be your place to save them, but you can always walk, offer a bit of advice and hope they save themselves.