I beg to differ.
A company has to keep books AR/AP and an investigator can easily determine the amount of funds tendered to said company and tax either entity as they see fit.
It really isn’t difficult at all.
Sure, but they can’t really figure out where the work is being done if it is being transferred digitally, not unless they subpoena email records etc. I don’t think that is happening now and a lot of companies are getting work done that can be transferred digitally from foreign locations.