There isn't and won't be the infrastructure for checking this kind of stuff.
Airport staff and airport police are not that clever or organised.
In most of Europe, the paperwork machine hangs together just enough to ask for a declaration that you and your passengers haven't got tuberculosis.
I think that most proposals which would require a huge amount of new procedures to be deployed Europe-wide, just to catch a small # of private pilots, will be dropped because nobody will have the balls to push it through, into a system which isn't getting paid to do the extra work anyway.
Like that 2005 DfT proposal to kick out N-regs after 90 days. The detection and enforcement mechanisms would have been rather interesting. No wonder it got dropped. It also had some very easy work-arounds (which I won't publish here).
Insurance would be the principal issue.