Land Hooper, while I agree with you that some pilots can be an arrogant bunch acting like prima donnas, I have to say that from a human point of view I understand your attachment to your hard working employees and see your arguments as valid; but, from my professional point of view, I have to say that pilots are not the only ones responsible for their safety in this case as you insinuate by saying that they should always be aware and wear vests. Same applies to your ground staff as well.
If there were any real safety rules out there, the contact between the vehicle and a pilot would be highly unlikely. There should be a marked path for vehicles and a marked path for pedestrians, all together with clearly marked possible points of contact.
I would say that this is mostly management's fault again.