ID required Open houses at sign in a good idea

(1) Its a safety issue for the sellers and the agent.
(2) People that don't sign in aren't buyers and probably don't belong in the house. After all if they drove to the open house they need a drivers license on them
(3) Agents do open houses so buyers can see them that aren't necessarily the list agents buyers when the other agent is busy with other buyers or has an prior commitment. Agents working in the best interest of the seller want to get as many qualified buyers through the door so the seller achieve their goal of seller the property so they can move forward with their other plans.