Perhaps just knocking on the homeowners' door and asking for permission would get the same result.One thing I have experienced is that with bandit signs in the ground, you will receive a high response-rate, but short lifetime of sign.

Also, I have been granted permission to share their contact info.

And just a few days ago the county denied permission on the grounds that too much modification needs to be done for that tenant to get occupancy permit.

Koel,It is easier to beg forgiveness than ask permission.

Due to the failure to include this statement, I had to request another court date for the judge to re-grant permission for Writ of Possession, even though it was granted during the first court session!

Do you yourself have cash, do you have a buyer already that wants the property,  do you have a title/closing agent lined up, do you have the recent payoff from the bank, has the buyer given you permission to talk with the bank, etc, etc.

Establish a monetary fine via your rental agreement as a deterrent to tenants allowing others to move-in without your permission.

To cover for the earnest money though, we try to keep some cash in the escrow account of our closing attorney to make sure we're covered.As far as your buyer's earnest money funds, those funds are technically separate and as far as I know (and I could be wrong) you're not really supposed to touch them, especially not without their permission.

And @Wayne Brooks is right, unless you have permission from the seller, the bank won't even tell you that property exists. 

Also, make sure that your contractor doesn't let anybody look at the house without your permission.