Restrictions can be put on any account Ebay pleases, at any time.

Its came out long ago (via two employees AND the CEO) that there are hidden seller limits that sellers dont know about, and Ebay restrict (throttles) smaller seller accounts without alerting the owner. They can turn them on and off like a tap, and do regularly. The basis of this was so they can forfil their contracts (which guarantee a certain amount of sales per month) to larger companies.  

Soooo... yes its possible. If you were a mulitmillion dollar business, and you had one small insignificant person (no offence! lol) causing trouble in a very legal sense, would you leave them there, with the possibility of that trouble building, or slowly cut them off so they just leave?