Blind dates seem to have a lot of potential to be awkward, but I still think the person deserves some degree of consideration. I think that this worked out well, since everyone agreed to reschedule, On the other hand, once you agree to the date, I think that unless new information about the date comes up that makes cancellation necessary, then you should go through with it.
It just seems rude to cancel any social engagement for no real reason or because you just changed your mind or a better offer came up. I don't know why a blind date would get less consideration than anyone else. I think the key here is to not accept if you don't intend to follow through.