Had one where the comms were good until the 'on the day' confirmation text. (I usually won't leave home without it, but I was working in her town so gave her some leeway. Eventually managed to speak to her around 11am (the punt was 12.30pm) but she sounded annoyed as I had woken her and said "I had a really late night, we need to put it back half an hour".
On one hand, I kind of admired that she did not try and bullshit me, on the other hand, I cancelled because I just knew it would be shit.
Thinking about the question, good comms are essential to me when making a booking and I won't proceed otherwise.