> Refusing to return security deposits is absolutely a low income landlord strategy.

Oh I've had this happen to me from a "high income landlord" in San Francisco. Penny pincher lady living in a wealthy neighborhood, repairing herself the leaky roof of the SF building she owns with duct tape. Tried to keep my deposit until, like the comment you're replying to, I threatened to bring her to small claims court. I had the deposit in my mailbox the next day.