Hi Susan- Also, unless the seller specifically discloses to the agent/ broker that there is a tax lien on the property, the realtor would not really find out about this on their own. This gets found out by the title search, etc- via the Buyer's lender.
I'm not sure about semantics on this- if the seller disclosed to the agent, then does the agent need to disclose to the buyer?? Dont' know about that...
If you need any further help with something, please let me know. Thanks, and good luck,