Yes, they will fine you $1000 per day that you rent out the property. Thats not a joke. No sense fighting it as its already on the law books. As you're in Clark County its not illegal until someone reports you. The money was good while it lasted but the only option you have it is to rent more than 31 days. Trust me. They have you on their radar and have created a file for your property and if you continue they will take you in front of the Council and present all of the evidence against you. Not only that but they will subpoena AirBnB for your rental activity for your property and that is how they will base your fine. If you want to see how it plays out just look up City Council meetings from about a year ago and everyone was getting fined into the tens of thousands. They eventually take about 70% off the balance but its still a good chunk of money and time expended.
In regards to your rehabilitation notice what state is the property in to get one of those? That is more than likely what tipped them off. Also, you can report your neighbors via a phone call.
By the time you get a notice they have already done all of their research and its been proven you are renting out and have advertised for less than 31 days. They will check HomeAway, VrBO and Airbnb. They will also post themselves outside of the unit in a nondescript car and watch your place and see who is coming and going. Sometimes they will even interview the people coming and going.
Next step is to immediately change the days you can host to 31. If you dont change it they will keep sending you notices.
Good Luck.