This is fixed through tax legislation, where there are "bright line" tests for whether or not someone is an employee.
When I was a contractor in New Zealand, I had an external office, my contract allowed me to subcontract, I used my own equipment and I didn't go to the parties.
When they wanted to send me overseas? We negotiated a new contract which included paying me hourly rates for the flight hours.
Unmentioned in the Canadian and New Zealand documents, they also typically consider length of service as a hint. If the contractor is with a single company for more than 2 years, that's a hint that they're not really a contractor.
USA [3]:
1 Behavioral Control (instructions, when, rules, evaluation)
2 Financial Control (equipment, expenses, profit)
3 Relationship (contracts, benefits, permanency)
Canada [1]:
1 Control
2 Tools and Equipment
3 Ability to subcontract
4 Financial Risk
5 Outside office and/or staff
6 Able to increase profit
New Zealand [2]:
1 Intention test (what both parties intend?)
2 Control vs independence test (who sets the rules?)
3 Integration test (are they part of the team? uniforms/parties)
4 Fundamental/economic reality test (who pays what?)
[1]:
https://www.canada.ca/en/revenue-agency/services/forms-publi...[2]: https://www.employment.govt.nz/starting-employment/who-is-an...
[3]: https://www.irs.gov/newsroom/understanding-employee-vs-contr...