I don't think it's when they accept an offer I think because when a property goes on the market they get so many offers they need to "hold ".
In some cases a property could have 20 offers. $10K - $100K over list , cash, no appraisal contingency and the seller wants to stop the 100s of calls and showings to sit down and accept an offer.
Where I am at. It's that crazy in sometimes.