Right, but that same "deadline" can be accomplished with a properly worded acceptance. And if it was an offer from a non-cash buyer who still needed to obtain financing, then the potential delays are increased.+1 on the "ask for a higher deposit", but I disagree on the financing: if the buyer had a rate locked in for x days (especially during an environment where the rates have risen a huge percentage-wise amount in a short time), I highly doubt the financing company would patiently wait on the sidelines while the lawyer plays the "let's see how many weeks I can draw this out" game and keep the funds at a pre-approved rate for weeks on end.
It's a minor point, but I just don't think the cash/non-cash thing makes a big difference if the person buying the property gets cold feet, hires a lawyer who wants to "make a statement" etc.