One could get a plane confiscated, in theory, for busting one of the French TRAs.
From the POV of an aircraft owner, I'd say that's he's more likely to get a confiscation (or a large fine, which the average renter won't be able to pay) with the average UK PPL renter doing that (no notams and/or doing dead reckoning over featureless N France) than trafficking.
Englishal - if you operate a really decent boat you WILL need to supplement your finances somehow. FAR more expensive than owning a plane
Thankfully all trafficking reported so far was done in G-reg... The CAA would just love to be able to catch an N-reg doing something like that.