> Take the example of GP's post, he kindly did the research for his ex-landlord until he convinced him. His ex-landlord may now see himself confirmed in that his approach to not caring is the right one, until the ex-renter brings up a very valid point.

I HIGHLY doubt land-lord didn't knew the meaning of "security deposit" and didn't return it immediately "because he didn't knew the law", especially when he was clearly ignoring the former tenant. He most likely counted on people not bothering to get it back when being ignored