no shows and time wasters are the main problem
Google voice and other texting apps has empowered them, they know they can do it and not get caught.
The percentage of no shows per city, months, etc. is hard to determine. We had a Dallas mafia but it was proven a myth by @Benjamin_Nicholas.
Many Dallas clients also didn't like the city's bad reputation, similar things have been said about Boston.
They also happen in other businesses, activities, etc.