Worker protections exist to ensure that employers don't exploit their position of power to take advantage of their workers. Full stop. Obviously that doesn't apply to the plumber you hired to fix your toilet or the painters the company hired to paint the walls but anytime you have a continuing open ended relationship when you alone provide at least a substantial fraction of the employees total income I have to wonder how on earth the same protections don't apply.

The situations where a contractor relationship applies are plain and obvious. Any time you have to ask if someone is an employee you are probably exploiting the fine line to avoid having to follow the law. Kind of like if you have to ask if you are actually committing fraud you probably are. Depending on which side of the fine line a judge comes down on you may or may not be punished for it but you aren't a better person for it.