It just came to my notice last week that Default Trust accounts too are sold here and may be escrow accounts too. This account sales happen privately and with the result nobody knows who is the new owner of the account and such accounts deserve a negative trust to prove that they are sold but nobody cares. I sometimes wish that Signature Campaigns are banned so that account sales will reduce in number.
It is true that accounts on default trust (as well as escrow accounts) are sold, however the purchaser has incentives not to scam with them because those types of accounts tend to be very expensive. The purchaser would likely be better off over the long term of acting honestly and continuing to offer their services and collecting fees for such.
With that being said, you should also not trust excessive amounts of money with any one person to avoid giving them incentives to run away (see maidak).