Earlier quoted context omitted.
That's an interesting argument. My intuition would've been the opposite: the title is much more likely to be dirty. 3 quick transactions in under a decade (and a fourth ongoing) means that many more opportunities for problems. Each transaction is a new opportunity involving a whole new set of people to be engaged in fraudulent conveyance or have a spouse pop out of the woodwork (as mentioned in OP). Maybe he figured…
Patrick's point about off-record transactions feels important here. Each on-record transaction leads to an opportunity for off-record transactions to be discovered! On-record ones are likely clean in some sense, whereas 10 years of no real estate on-record transations means nobody has looked. But to your point... the more people involved, the more moving parts involved.
On the other hand, I would expect both types to correlate with one-another, tied together by a shared factor of "activity level."