Professional companies wont and they will walk away from the doing jobs like that. Just depends on how professional your company is and what image you want to portray, personally I would rather stand my machines in the yard and let them rust than put them out there for nothing or with an unqualified operator, but maybe thats just me.
The problem comes when people start to lower their own standards to try and compete with the dodgy companies willing to fly by the seat of their pants and the market just becomes a free for all bidding war.
Personally I think the courts are also to blame as when the HSE or EA do manage to get people into court they slap them with fines like £4,000.00 which is no deterent at all stick another 1 or 2 noughts on the end of them fines and then you might stop them but until then its just another problem for the industry to try and overcome.