Extremely difficult seller

[Ben Mitchell]

Had an interesting situation this past weekend. I'm trying to buy a house. I submitted my offer (722 with escalation to 731) against a 720k  offer. 

The other buyers agent indicated to the sellers agent that 720 was their best and final. The seller told his agent and my agent that he would sign our offer the following morning. 

The seller (not the seller agent) decided that wasnt good enough and called the other buyer agent at 9pm on Sunday night and told him the details of our escalation clause and said if they would beat it he would sign their offer. 

So yesterday morning, the seller agent was blindsided by a higher offer he didn't know anything about. 

seems kind of unethical by the buyer agent no?