I have often found that new users to Airbnb seem not to have notifications turned on and I too have been frustrated with the lack of communication. I do not host in my own home, but another space, so it is a bit different, but still makes me nervous when I don't hear anything from the guest. However, in each and every instance, the guests have been fine and there have been no issues whatsoever.
That said, as @Julie143 stated, one way you could attempt to avoid this is to not allow last minute bookings. Also, you can turn off IB and when a guest requests to book, if you hear nothing back from them, just decline their booking.
I too was a bit worried about declining too many bookings-had a 97% acceptance rate, but then had a rash of 3 requests in a row from newbies with no profile info, no photo, no verifications, etc, so my acceptance rate went down to 91%. I contacted Airbnb about it because I found two of them to be suspicious. However, I was told that dropping below the 88% acceptance rate is not a problem and the more important thing is to keep the response rate high-100% if possible, as mine is. I asked again to make sure and was told flatly that I should not worry about dropping below the 88% rate and that there would be no consequences for me. I suppose for me, since I'm in a small market, my ranking in a search wouldn't be much impacted, but I'm thinking that it could in a larger market.
