Is this a problem though? I a lot of countries you can open a 1 shop company, and any two companies can sign whatever they agree on into the contract. Of course some higher level laws may void (parts of) the contract.

Do you think that “nature of the relationship” is more important than wording of contract? Why?

If countries hate the idea of 1 person shop contractors they can still ban the “shadow employment” via higher level laws. If they don’t I don’t understand how this is a problem.