Belgium is the example of a country who implements the rules as they can be. What they do is date the entry point of EU citizens, we don’t. An EU citizen can remain in Belgium for up to 3 months, as per a Holiday visa. After 3 months, unless they can prove they can support themselves or that they have employment, then they can be deported back to whichever EU country they came from.
There’s obviously a cost to policing this, and the reason it’s never been done over here, is because the Govt knew fine well that overall EU migrants make a positive contribution to our economy, so they’ve never bothered.