You guys need to know about common sense.
Most of these younger fly by night girls want a booking NOW, and they don't want to send 50 texts back and forth answering annoying questions, they will double book because last time they waited for a guy, and he pulled a no-show, she learned her lesson. So now, she will double book a bunch of clients, who ever shows up first - wins! Any other guys who bother to show up and find themselves getting no response, that is the reason why. It's just smarter to do it that way, so the lady's time doesn't get wasted again, she doesn't get burned again.
Put yourself in her shoes, you are desperate for cash and you need it ASAP and can't afford to loose business. If some stranger you've never met wants to book an appointment say 2 hours later, and during that time, one of your regulars or some other dude wants to come within 30 mins, and he shows up, books the time slot and pays you the money, its a much better option...instead of saying No to that regular client, and then risk getting stood up by mr. 2 hours away guy (happens ALL the time! HUGE slap in the face, but when this happens its a good idea to notify Mr 2hr guy to cancel...but some women will just double book all within the same time slot and are too busy with cock in their mouth to get to the phone and cancel with the other ones)
For most SP's who do this to get quick cash and don't have time or patience to wait around, its the sensible thing to do. Unfortunately it's due to the massive amount of flakey guys and no-shows who ruin it for the nice guys who do actually show up.
Girls have brains, if they get burnt once, they will avoid the same situation again in the future. It's like the lab mouse who avoids getting tasered and looks for ways to get the cheese reward.