is this really the reason for the negative ?
She received u 5 times before, you didn't repay her for the good times but she makes some mistake and wham! U punish her !
She/the maid probably overbooked that's all.
I'm not saying this behaviour is not inconvenient for a punter, as I have been left disappointed terribly once or twice before, regardless of the reason.
I must now second the weirdo classification.
Seriously, there should be more types of negative reviews as this most likely qualifies as a tiny insignificant harmless negative whereas a standoff with a sergei like I've had twice would come as the more serious type. It's not fair either to other punters who search for a chick and notice she has 4 negs don't check what kind of negs they are and continue searching, as it so often happens to me.
What are you on about? 
It would be far too complicated to having different shades of negative as you suggest and even the award of different shades would still be subjective.
In any case, this is clearly a
justified negative: She not only ignored him and kept him waiting for 15mins, she then tried to cut the agreed time before chucking him out! So a totally wasted journey.
By luck, if he lived nearby and/or managed to line up a Plan B is totally irrelevant. Many of us travel at least an hour each way for a punt and aren't impressed when an escort fails to go through with a booking at the last minute.
Therefore, this negative review is extremely useful to us and that is the whole point of this site - to save punters time and money.
And, what's more, the comment has been backed up by other punters.
Saying it's a "tiny insignificant harmless negative" makes you sound like her pimp or, at best, a whiteknight.

Thanks for the review, OP.