I'm giving Mic a one-star review not because he didn't show up when we were due to check in (effectively cancelling our reservation) but because he then refused to recognize that the failure was his. Instead, he argued that we had cancelled the reservation by going somewhere else and so he didn't want to refund our money. (Fortunatley, AirBnb agreed with us after reviewing the case, and we eventually got a full refund from them.)
We went to Dublin for WorldCon. Because of the way our flights worked out, we arrived a day early and spent the first night in a hotel. We went to Mic's the next day, which was the first day of the con. I messaged him at 8 that morning to ask if we could check in at 5pm instead of 1pm, since that would fit nicely into a gap in our programme. He hadn't replied by 9 and we had to go to the con, so I wrote to him again and said we'd stick with the original plan and check in at 1pm.
We went to meet Mic at our check-in time, but he wasn't there and didn't reply to text messages, calls, or messages on AirBnb. After waiting for over half an hour without any contact, we gave up and decided to book a hotel instead. We didn't want to stay in the street with our luggage and with no idea of if/when we would hear from Mic, and we also wanted to get back to the con we had come to Dublin for. It took some running around and cost us most of the afternoon (as well as a fair chunck of money) but we managed to get a room and get back to WorldCon.
Mic called me at 4pm (when I'd just gotten back to WorldCon) to apologise and explain that he had to go to the hospital because his friend had an emergency. He offered a free night to make up for it, but I explained that we had already booked a hotel and paid for it. I told him we'd be asking for a refund and I hoped he'd process it soon.
Mic later replied via AirBnb message and said he had expected us at 5pm, so according to him we had cancelled on the first day and he wouldn't refund our payment. However, when he called he was very apologetic about missing our appointment, and he also never confirmed the change in check-in time. I understand that he was pulled away by an emergency, but since he wasn't there and didn't contact us (he was out of touch from about 8am to 4pm, though we were due at 1pm), it's clear to me that the failure was on his end. That alone is not enough for a one-star review -- bad things happen sometimes -- but his refusal to recognize the situation and the fact that we had to involve AirBnb make me want to warn people who might be dealing with him, especially since one of the reasons we chose his place was that it had many good reviews.