The line between the client's file and the contractor's file
Confusion here creates two opposite problems. Some clients collect nothing, then discover during an incident that they cannot say who was in the building. Others collect too much, holding copies of visas, passports and licences for people they do not employ, which creates a privacy obligation they never intended to take on. The useful middle position is a written confirmation from the contractor plus a record of who attended.
That middle position is also what most reviewing parties actually want. A head contractor asking about labour arrangements is generally checking that a chain exists and is accountable, not auditing individual documents. A confirmation naming the entity that engages the workers, the checks it performs and the individuals attending the site answers the question without moving personal records into the client's custody.
