I see a lot of people jumping on this guy's case. If you want to know who it is, I suggest shooting him an email since he clearly doesn't want to make their info known publicly. You'll look less like drama-hunters that way haha!
As far as the OP's post, I always have a plan B lined up (or C, D, E, F). Most hobby girls are kind of flighty which sucks. Sometimes it turns out that they double booked their time. Other times, that may not be the case, they simply didn't "feel like" seeing someone and even though you were almost there or whatever, they changed their mind and felt they were going to wiggle out of it with a poorly formed excuse.
Sometimes the excuses women give are real (it happens). However, I make a mental note of these encounters, asses them and if they seem valid, I give them another chance. If not, I move on and X-them off my list.
Having a backup is almost always the best plan though. For me, there is a certain satisfaction being able to tell someone, "Sorry, I went ahead and scheduled with someone else."