But you should ask for a list (as Rockin' suggests), and make them sign a note insisting that these are the only names that would be included in any obligation.
Most listing agreements have a clause that protects them from their customers finding the property through an agent but buying it FSBO after it expires. Check your listing agreement to see if there is a period of time that protects agent's customers after it expires. Most standard contracts allow for from 90 to 180 days but check your document to be certain.
There isn't a waiting period per se, however there should be a protective period in the listing agreement, typically 30-60 days for the agent.
You can market your home as a FSBO at any time, however, if you sell (within the 30-60 time frame) to a buyer that was attracted to the home (i.e. attended an open house, viewed the home with an agent, expressed any interest to the agent) during the listing period the home was with the agent, then you would owe the agent the full commission. In other words, the agent was the procuring cause of you finding the buyer, therefore the agent met their contractual obligation and should be paid for the result.
I hope this helps! Best of luck to you!
ERA United Realty