Legality Question for Open House Strategy

[Steve Meyers]

Hello, had an idea to do a contest at my open houses to give away a free home warranty as a buyer credit through escrow.  When buyers come in I'll ask them if they'd like to enter for a chance to win a free home warranty, if they say yes I just ask them to sign the sign in sheet and they spin the wheel.  If it lands on a free home warranty then they would get a certificate stating they would receive a free home warranty as a buyer credit through escrow.  What is the rule on a strategy like this?  Is this considered soliciting buyers by giving this away?