I heartily agree with you there.Ahh the good ole "stuck at work/last minute assignment excuse" that they just so happen to find out about a hour before you are supposed to meet. Nice try ladies, I've used that one before my self and I'm not falling for it. Automatic end all communication if they try that on me. You get one shot with me and that's it.
Then again I need to add that I am for example in a job, where I can be called to work with very short notice. And usually the shorter the notice time is, the more they actually need me. Of course I can refuse to come, but it is quite negative thing to do in my books. It can be really annoying if you have booked something already, and I don't really know would I try to reschedule or would I miss work. This hasn't never happened, thank gods, but generally if I am going to work with short notice, it lasts from 15 minutes up to max 2 hours, so I guess that rescheduling could be an option and even perhaps asking people to pick me from work. But that is just me. I am only saying that sometimes it isn't necessary an excuse.