The new law only targets "advertising" your listing for less than 30 days it does not say you can't "book" your apartment for less than 30 days, you only can't "advertise" it.
So what if all NYC hosts just change their minimum night stay to 31 days, and in the detailed description state "NYC prohibits advertising less than 30 day stays, message me in regards to availablity of the apartment and the length of your stay, and I will accomodate your request" Or something to that effect.
Eventually guests will learn to read between the lines and message you about stays less than 30 days. We definately need some sort of work around to help us out.