This is an odd posting on Redfin.
http://www.redfin.com/WA/Seattle/3221-2 ... ome/123116
Does the seller really think that someone who is buying, and trying to get the best price, is going to help keep a secret? If I was serious about buying this place, the first thing I would do is go inform the renters that their place is being sold from underneath them... with intentional deception. When they leave the next month, the seller's bargaining position is weakened.
Maybe it is really common for landlords to not tell their tenants about a possible sale, but asking potential buyers to be an accomplice seems silly. Does a landlord/seller think that having current renters means as much or more to the potential buyer as it does to the current landlord? I think not.
I have half a mind to drive by with a note just to help out another renter.