If the option check is not receipted, what is the proof that it was actually delivered late? Option checks are commonly delivered to brokerage offices with only contract document page 9 so the front desk personnel don't know it is late. It may be days before the listing agent actually picks up the check and delivers to the seller, so how long does the seller have to reject? Is the check returned to the buyer address in contract paragraph 21 which is often just an email address?
A receipt is one form of proof. If the person who delivers writes down the name of the person at the front desk, date and time of delivery, then that can serve as proof. Some people take "selfies". (I did a video on this one time.)
As to knowing if late, the brokerage should have policies about receipting option checks. I have encouraged this for years. Maybe the front desk doesn't receipt - only the listing agent or someone with access to the contract dates. The issue of days before the listing agent picks up the check is a little more problematic. If the check just sits up at the front desk, I think the listing agent may have some liability to the Seller for "holding" the check. Hopefully your office has or will create some office procedure for these scenarios. Thank you for watching our videos. I hope Allegiance Title Company has earned your business.