This was brought to my attention a couple of months ago via a TripAdvisor thread after I had booked an Airbnb a couple of months prior. I immediately called Airbnb (Who still actually tried to tell me not to worry about it and that my reservation was perfectly fine) to cancel my reservation and reimburse me for both the reservation and any fees to which they did.

Both Airbnb and these Home Owners are well aware it illegal to rent out short term rentals, but do it anyway in hopes they don't get caught and can pocket a few bucks. Obviously I would have preferred to stay in the apartment that I rented, but wasn't willing to roll the dice since I'm going on a high volume week (Grand Prix) and I guess that the enforcement agencies in Singapore will be on high alert during that time.