This is not that uncommon. I have experience it several times with my Efty BIN domains. In my experience it is simply non-serious buyers who never intended to purchase it. I had to remove the BIN option from one of my high traffic domains with traffic primarily from South America because I was getting 3-4 escrow transactions a week on it, and they were all bogus. The Escrow.com signup is very simple and quik and is not a barrier for any serious buyer. You will always get people who just get their kicks out of submitting forms. Not to worry.