The Seller shall have the right to keep marketing the property, and to receive alternative offers to purchase the property.

Should the Seller receive a bona fide offer to purchase the property from a third party, at any stage prior to the fulfillment of the suspensive conditions contained herein, which the seller considers more favorable than this offer to purchase, the Seller shall be entitled to accept such offer to purchase.

If the Seller accepts an alternative offer, the Seller shall notify the Buyer that the Release Clause has started to function immediately.

The Buyer shall then have 24 hours to fulfill all suspensive conditions contained in this offer to purchase. The Buyer has to commit within this time frame, to taking transfer of the property, free from said conditions. Failing compliance within 24 hours, this agreement of sale shall lapse and become null and void, and neither party shall have any claim against the other whatsoever.

Bankapedia's Take

The 72 hour clause is often put in there, with little to no choiuce of actually being executed, but as a way to make sure the buyer puts in a decent offer. A little real estate agent gamesmanship, if you will.