It's a losing strategy.
I found I was much better off if I could give the other side real wins.
Especially in repeated games.
Single-round best strategy is squeeze and defect.
Good negotiators find trades that are valuable for both sides of the table. That's how you negotiate well.
That does not sound realistic for a normal-homeowner U.S. real estate sale. There are generally two Realtors and a title company as professional intermediates in the transaction. The seller may only know the buyer's name if the seller spends time reading routine paperwork - which those intermediates create and handle. Why would the XYZ agents visit the seller - when the buyer's Realtor, buyer's bank, and title company have so much more information, insight, and experience on the matter?
I can see it as buyer (you want a house, not a title insurance claim). But as seller...even having your own atty. involved seems pretty odd. It's the job of the Realtors, title company, and bank(s) to judge the buyer's money, and call it good or bad.
(Or did someone offer to buy your acquaintance's house, with no intermediaries, for a briefcase full of cash? That raises enough red flags that you could host a birthday party for Karl Marx.)
Another tidbit: in NYC, most people use an agent when they rent an apartment. They charge one month’s rent.