Subject to Selling

[Brian Smith]

I have read about the advantages of buying with a subject to clause. What are pitfalls of selling a property with a subject to? For example:

Buy a property for $30,000
Repairs of $20,000
Mortgage of $50,000 at 7% interest

ARV is now $75,000

Sell to new owner on a subject to: for $75,000 with say 9% interest.

If the new buyer defaults, just resell? How do keep the lender from activating the DOS clause?