If you're using Mycelium android wallet you probably see ads in the media flow tab of Mycelium Exchange (cryptoexchange.mycelium.com), advertised with big bold letters as a No KYC exchange.
A few weeks ago, I decided to give it a try and deposited around $100 worth of crypto. I performed a trade, but when attempted to withdraw, I got a message on the screen saying my withdrawals had been frozen and telling me to contact customer support, which I did.
Customer support demanded me to provide "Source of Funds (SOF)" and complete the KYC process.
I provided them the source of funds as I didn't mind sharing such info, but declined to go through the KYC process, saying that the only reason I used their exchange was that it was advertised as "No KYC" and I'm not comfortable with sharing my sensitive info with 3rd parties I do not know or trust.
Long story short, they unblocked my withdrawal and I was able to transfer my funds out.
The stated reason for freezing my withdrawals was:
They were “frozen” because the AML compliance department had concerns about the quality of the BTC that was deposited on the exchange.
So that's something to consider if you're thinking about signing up for that exchange.
Before I signed up, I couldn't find any reviews or feedback on their service, so I thought sharing my experience here could be helpful to others. I'm saying they are a scam, but I don't think we have a board for service discussion (if so, mods please move).