* Companies are not your employers per se, but your clients. As such, they are not entitled to direct you in your work.
* Of course, your clients have a right to say what they expect for the rates they're paying you, but only as it relates to the outcome of the project.
* It's your right to decide when, where and how to get the project done.
Natch, it's wise for you to satisfy your clients at the project level, if you wish to get paid and receive favorable referrals for landing more contract jobs. But that doesn't mean you must allow a client to control you as an employee. That's against the law.
In other words, by U.S. law, an employer cannot classify you as an independent contractor, then dictate when, where and how you work, as though you are an employee. It's all about degree of control and independence.