I should think the bulletproof vest manufacturer would have various checks and codes for different models and specifications though this did happen with a satellite when the Europeans measured in metric, the Yanks in imperial and built half of it each.
When a train driver cocks up it doesn't take long for people (including his employers) to hang him out to dry.
If you choose a profession where there is a high chance of somebody being abused, raped, maimed, paralysed, burnt or dying if you cock things up then you have to be prepared for people, regardless of being armchair experts or genuine vocational experts to start pointing fingers in your direction. This goes for many occupations but social work is at the sharp end of this blame and shame culture due to the nature of the work & it's victims.