Re: Naivety...
"Howeve I'd have hoped that this would soon become a case between customer and supplier and the employees will be taken out of the firing line."
If that's the case, then they probably will be -- but they may have to go to court and prove that they were operating in good faith and it's their employer that screwed up. I suspect that if that's the situation, then the pentesters may be able to win a rather juicy lawsuit against their employers, too.