What does it mean (and why) and Is this done by the cuddler or the administration?
Admin.
Varies with the reasons.
if it's a Pro, could be because they did not comply and add a card to their account. Or something else.
If it's a a regular user on the site, it could be for many reasons -- most likely didn't pay a required fee/deposit/no showed and the Pro had cancellation fees, ect. or questionable messages can lead to that as well, but more likely a ban.