Alll they need to do is ground the aircraft subject to investigation for 2-3 days every time they land or even once or twice a month and then having your own transport is useless because you could never garantee it would be available when you wanted it.
Like I said we'll wait and see what happens. As one of the most prolific posters on the Private Flying forum pointed out, it would appear that most European states (unlike the UK) have not decided to delay implementation of the licencing compliance requirement unitl 2014 for foreign registered EU based aircraft and therefore as of 8th April they are apparently flying illegally if not in possession of EASA licences and if based in a state that has not delayed implementation. However there is little evidence that in the short term there will be any sanctions taken against them...I look forward to hearing the details of any cases that emerge.
Like the Italian private aircraft tax for example there is often a delay between a law actually being past and the enforcers on the ground actually being aware of it and being in a position to enforce it.
I would hope however that simply being an EU citizen, flying an N-reg in the EU on FAA papers would not, in of itself, be enough grounds for arrest/and or impounding of the aircraft. I would have thought that the authorities would need strong evidence that the aircraft was actually EU based as well to take action.
Ultimately what I think it will come down to is the inclination of individual member states to crack down on suspected offenders...something again which will be interesting to see. Who knows, this could be a massive non issue, personally I just went and got an EASA IR... bit more of a pain for ATPL or indeed (as the article points out) for people who are only planning on staying in the EU for a few years.