wow! talking through hat much?
Independent contractors most certainly can be forced to use and buy uniforms. If the contract says "provide service X while wearing uniform Y" and you accept the contract you most certainly are required to wear uniform Y. Just like a contractor can be required to use specific materials for a job.
A contract can also require when a job is done, such as "paint the walls of our building using [specific brand and color code] paint, work will be performed after hours between 5PM and 8AM, to be completed by November 15th 2015.
The difference between a contractor and an employee is rooted in the negotiation and powers of the parties.
If the worker answers to a boss for day to day instructions, has little or no say in the compensation level, is contractually prevented from working for others, paid on a regular time basis and is scheduled by the employer then they are pretty much sure to be considered an employee.
If the worker is just required to meet deadlines, is paid by the job, has freedom to work elsewhere, and freedom to hire their own help then they are generally going to be considered an independent contractor.
A contractor cannot be fired. They can lose the job if they fail to meet the terms of the contract, but for the length of that contract they are not susceptible to the whims of a grumpy PHB, and the contractor has the same right to initiate a breach of contract suit as the company who hired them.
The grey areas that are showing up in recent class actions are pretty much all the result of companies wanting to avoid the responsibilities of employees, such as unemployment insurance, workers comp, disability, etc, but wanting to regulate the worker/customer interface to preserve a consistent corporate image.
Because these are large corporations contracting individuals to a large extent the contractor does not have any power of negotiation, the corporation writes the contract, and contractors can take it or leave it. This does introduce a bias against the independent contractor classification.
I think in many of these cases the workers will win, because the company is really trying to say "you don't work for me, but you have to represent me in a strictly defined way".
If a company really wanted to do this with contractors the right way they could write a contract that regulated the workers as strictly as they wanted, then put the contract out for bid. This would shift the negotiation power toward the worker, let them name their own price, but it would also cost the company a lot more money, because people bidding on a contract are either going to name a price that actually reflects their money/time investment, or if they grossly underbid to get the job, they will not be able to actually fulfill the contract requirements.
An actual example:
Your mailman is a government employee, benefits, insurance, the whole kit and caboodle. In rural areas he is actually required to provide his own vehicle, but is an employee.
The truck that takes your mail between sorting centers is probably an independent contractor. That particular contract has pretty strict time requirements, and a bunch of hoops to jump through (after all, it is a government contract) but the government is not concerned about that contractor representing them, because they do not interact with the customer. The contractor provides and maintains the equipment, hires their own drivers, and bids competitively to get the contract every time it comes to an end. They run some pretty ratty trucks sometimes. I have seen U.S. Mail painted on trailers that have other logos just painted over, being pulled by tractors that look like they were purchased third hand.
If the contractor underbids the job he will either suck it up and lose money (if they have the capital to do that) or will be forced to break the contract.
But any way you look at it a contract can be so specific as to specify the brand of toothpaste the contractor uses. The specificity of the contract is not the primary differentiator between the employee and contractor classification