"are not reporting this contractor tips"

Is this what you mean: The person doing the work got paid by the customers of their contracting agent (their customer) and not from their contracted customer?

If your taxpayer truly is independent, one customer would never report what a different customer has paid them.

Example: An independent hairdresser who rents a booth at a salon, also gets leads to a senior home to work on site there, and has to pay the salon owner a commission for these sales. Meanwhile, while at the senior home, the hairdresser gets tips from the seniors.

This has nothing to do with the salon owner. These are separate customers.