It does and can happen, it seems all countries are tightening up.
They can check phones, flights, ferry crossings etc.
My cousin has been travelling from London to Belgium for a few years now. He has been staying with his girlfriend there, sometimes for a few weeks and sometimes for a few months at a time.
In early December he was told to return to London, and cannot go back to Belgium until March.
He now has to decide which country he wants to reside in, pay taxes to etc. in U.K. or in Belgium.