A better strategy is to make it undesirable to rent for one night by increasing the admin costs associated with a single night stay.

Middle to Upper Class individuals are moving into areas in Brooklyn that a few short years ago were absolutely undesirable for the reason you mentioned.I would be lying to you if the idea of relocating altogether hasn't crossed my mind....multiple timed.

I made the mistake of purchasing in an undesirable neighborhood.

Several things are red flags: the low purchase price, especially for a duplex, almost certainly means one or more of several things: it is in an undesirable neighborhood and it will be difficult to manage, they didn't do much on the rehab and it will have some very significant differed maintenance, it will be very difficult to exit without a loss because it won't appreciate. 

I do this with undesirables moving in to my units.If you can serve the notice the police will arrest him for trespassing.

But when I compare this investment versus trying to house hack in an undesirable neighborhood of Brooklyn it seems like a no-brainer. 

Buy undesirable wetlands, marshes, and DEC protected lands that could be sold for pennies on the dollar.  

Investing in "undesirable" areas is never wise... regardless of price.

Most of these homes are narrow and make for very small rooms and are undesirable.

Most of the homes are in very undesirable areas as well... so even renovating the homes may not make up for the equity problem as there isn't enough value add opportunity.Homes that are in fair areas (C or C-) may be able to break even with a rehab as we had one that was close.