Thanks to everyone's replies. I heard from the two companies listed on IS that I already had a relationship with. The platform is legitimate. Neither had anything to say about the cost other than they did not require it.
It does the question in my mind why a platform that needs to recruit both MSCs and IC's would choose to do something like this, Just about every MSC warns people about ever paying. I still don't know what it is they verify as the MSCs said they don't require it. I've asked and the question was sidestepped. Are they trying to verify my identity? Why? The IRS does not require that. And since a digital document like a photo of a driver's license could be faked, there's no one out there that I've seen who provides any kind of certification of identity online.
It appears that this is a way for the platform to raise funds from ICs in addition to the MSCs. They're not doing a background check here. I might understand the need for that for certain jobs but the only time I've ever seen the need to pay for one was when I applied for the background check myself.
So here's my summary at this point, trying to keep in mind that I may never get all the facts, the rules for this forum, and our life in today's litigious environment. I speak for no one other than myself.
*Ethical.........At this time, I can't give a positive response. And even if the fee is unethical, it may not apply to the rest of the platform.
*Caution Flags: Yes.
*Value for this fee...............So far, I am not sure what is performed, who performs it, what it certifies, and which MSC's want it. Until someone tells me otherwise, it appears you get nothing for the fee. They may set up two classes of ICs in the future--paid and unpaid. There is a business case to be made for that, but not at the present that I can see.
*Trustworthiness......Hold on to your wallet. I am no longer concerned about identity theft or fraudulent charges. But I will not pay them a cent unless it is 100% clear what I am paying for and they are completely transparent, the MSC's have confirmed they require it, I have verified what they tell me and, it provides value to me.
*Judgment for choosing to do something that is recognized to be a sign of a scam? Highly questionable.
*Legitimacy.............Yes. The MSCs are responsible for the job listings. They are not a scam set up to steal my identity. If that is your only requirement to sign up for the platform, I've seen no evidence to the contrary,