From a practical matter the Seller really has no "tools" until the good faith deposit has taken place.
In my discussions with CAR Legal it appears to come down to while there may be a valid breach of contract argument, proving the Seller has been damaged may be difficult.
I also spoke with a 20-year Real Estate Mediator whom boiled it down to these three pertinent facts:
1) In practice, the question of damages has to be proven,
2) There's likely no deposit in Escrow, and finally,
3) The Buyer has all of their contingencies to fall back on.
When this type of situation(s) occurs it seems best response/practice is to get the property back on market ASAP! In my case, I sent a cancellation of contract with the reason being â€œBuyer request and/or anticipatory breach.â€
Of course, these situations are not always the same, so a review of the facts by a legal advisor is many times a prudent step.