I may well be a moron, but thanks for the benefit of the doubt.
The papers are very good. Unless you are an expert (and I am not) you cannot tell. Actually, you can get in trouble refusing papers unless they are an obvious forgery. (They are always more willing to go to bat for the illegal and the employee rather than the employer).
There would have to be a time frame, say 3-5 days to check. Much highering is done in the field on the morning of the pick. Difficult to get everything done.
[Much highering is done in the field on the morning of the pick. Difficult to get everything done]
This is another problem with the construction industry. A lot of labor is pulled from union halls. You the standard proof of identity from union labor workers.