Their pics make them look like hip witnesses. Just seems like an odd arrangement. And odder to post on Craigslist.
I agree with you now, and yeah, that type of living arrangement is discouraged among the JWs. But why post on Craigslist? When you're budget is tight, usually you just put the word out in your local congo and you can find an overpriced property some JW wants to rent out. They must not be regular pioneers and must not have family in the JWs.
Supposedly JWs are more honest and decent than your average person. Maybe they think some one will offer them an incredible deal based on that theory.