It seems that fox.exchange is doing the same thing recently, except that they dont need for users to register but they will (most likely) randomly ask for people to send documents in the name of KYC/AML compliance but they seem to be doing it to scam people. You can see a lot of people are giving bad reviews(Trustpilot, Bestchange, forums,...) for this kind of issue.
You can check my post about this (https://bitcointalk.org/index.php?topic=5318850). Just go to the links i've listed and you'll see that recently a lot of people are having these issues. They were the ones that got the less fees in the Bestchange list recently, i think the FOMO by people trying to get in and buy different crypto and try to make money doing that has led them to make such scammy tactics cause of course most people wont send documents to a non-registered exchanger and will likely leave the coins and move on with a loss.

I hope im wrong though as i am still waiting for a refund.