@Brian2036
I think that @Jo719 has a key safe/self check in system so she's not waiting around for the guest. It's still annoying to have to rush the turn over for a guest that doesn't even have the courtesy to then let you know they are arriving later. I doubt that many guests even think about this though. They often seem to imagine that the Airbnb lives in some little magical bubble that is just for them, with no guests staying before or after. It's not logical obviously, but I've noticed this many times.
Like you, I do an in-person check in and used to experience the same problems as you over and over again. Guests just seemed to assume that you are there anyway, so as long as they show up within the 3-9pm check in window, no harm done.
I had to make it crystal clear that they needed to specify a time in advance and let me know if they are running late and I also really stress the check in time is between 3-9pm, no earlier (later will incur a fee) and no early bag drops either. Of course, I do make exceptions to this, but only if a guest asks nicely and it fits with my schedule anyway. It's a shame to have to get so strict about it but, after being mucked around countless times, it was either that or stop hosting!