3 pages of discussion is way to long for this topic. Don't overthink it. There can be several reasons why clients prefer last minute booking. They could have an unpredictable schedule as well and realized that they have extra free time, they could be DL and perchance got a free time before they head home, they don't have a regular work schedule....etc. You can put in your ad that you are not available for last minute scheduling and require x-hours of lead time, autoreply if you are not available, or an answering service as if you are working in a spa. Otherwise, just say no you are not available when asked. Unless you want someone else to manage your inquiries, you will have to deal with last minute bookings. That's the nature of the business. Insanity is doing the same protocol and expecting a different result.