The danger in the future, and especially in Europe, is that what might be a SB in FAA-land tends to become something mandatory in EASA-land.
A very good case in point is the Cessna 337 Skymaster that has a looming SID (Supplemental Inspection Documents) on it's wings. It requires the owner to do a tear down of the whole wing and do a one off inspection, Eddy current, dye penetrant, x-ray, the works to prove that it's safe. This will most likely run about $60K, well above what many 337's are worth. Now, in a part 91 operation, or private use if you wish, this is optional. In Europe, they have said that any SID that comes into effect will have to be complied with - they don't make an extinction between commercial and private use. This has the effect of, overnight, making any 337 worthless that's on the European register.
But what's more worrying is that these SID's are instigated by Cessna, they don't stem from an AD or the FAA. It's because Cessna wants to sell new airplanes - as simple as that. They're sick of people flying around in 40 year old aircraft that don't break down enough for the bean counters so they invent this inspection scheme. And you can be as sure as the sun shines that they have future SID's in place for all their aircraft and will roll them out in time to gradually force new sales, obviously starting with the least supported or loved models, i.e. Skymasters. It makes perfect business sense.
Ultimately, the problem with this (once again) is that in the US what's optional for a private owner, will in Europe be mandatory. This has potential catastrophic results unless EASA in the future will grant exceptions or make a distinction between private use and commercial. Taken to it's logical conclusion, and if all manufacturers follow Cessna's SID lead, they could make it so cost prohibitive that all GA flying in C of A aircraft in Europe could be threatened. I doubt that will happen, but it's a possibility.