Idea HN: Cross check rental listings for valid cert of occupancy

A strange thing happened to one of my friends. He discovered that the converted church he was renting an apt in for $6k a month in Williamsburgh (NYC) didn’t have a Certificate of Occupancy. This meant the landlord couldn’t legally collect rent, nor could they collect back rent should they ever get one. So my friends lawyer advised him (and 30 others in the building) to stop paying rent. This was over a year ago and the building owner seems unwilling or unable to make the changes needed to get one. There are many such properties in NYC and usually people are paying rent that don’t legally have to do so. A useful tool would be a mashup between craiglist apartment listings and the cities C of O database. This would effectively be a directory of free NYC housing. One could sign a lease, write a check for first and last months rent check, move in and immediately stop payment with no legal recourse from the delinquent Landlord. Depending on where you fall on the political / economic spectrum you’ll either love or loath this idea, but it should be built either way! I’d do it myself but I’m busy working to decriminalize entheogenic plants in NYC, do someone please build this for fun and / or profit (priority alerts for free apartments in your fav hood?).