Hi @Natalie725
I've read through 2 pages of responses, but not all, so apologies if I cover some of the same ground.
I am a remote host and I have been through what you are going through several times.
This is what I have done to mitigate..
I de selected "self check in" and changed it to "host will greet on arrival" although theoretically self check in IS available on my listing. In my area I learned the hard way that most guests saw the self check in icon, didn't read the listing, didn't read my messages and didn't give me an estimated arrival time - all what you are experiencing. I also learned that the sort of guest who prefers self check in over being met and greeted is NOT the sort of guest I prefer to host. this is just for me personally in my area. Of course it may well vary for other hosts in other locations, but I found 100% of my guests who booked when I had self check in activated were distant, aloof, unfriendly, entitled.
IN my pre booking message ( I have IB) I ask for an approx arrival time.
In my house rules I have a paragraph like this "CHECK IN starts at 2 pm onward. Please let us know when you plan to arrive. Plans can change - JUST LET US KNOW - no one likes hanging around waiting for 2 hours. We DON'T live nearby. There is no front desk reception. Just us. Waiting"
I have a code word hidden in my house rules. My last pre booking message is "have you really read my house rules? What is the code word?" Which usually ensures that guest at least scan through the house rules adn see the bit about arrival time.
If none of this works and a guest doesn't let me know after I have messaged them, I would get airbnb to ring them and tell them I have been trying to contact them and they are not answering. ( I could ring as well, but I prefer to get CS to do it as it lends a bit more gravitas to the situation). Almost always, this brings the guest to heel - they then respond and apologise. Sometimes it's because they are inexperienced and just genuinely didn't realise and that's fine.
HOWEVER if I still get no response, or an unacceptable response. I would have no hesitation in cancelling. A guest who cannot be bothered to communicate after all these prompts is going to be TROUBLE.
I also get Cs to ring a guest if they have kept me waiting more than 1 hour. If thye've said 2 pm and it now 3, I put the wind up them. I realise things can go wrong of course, but unless the circumstances are VERY extenuating, it's not ok to not communicate a change of plans.
Not foolproof but has helped enormously. I think my genuine shift in attitude, which is , if you stuff me around, I'm not putting up with it, I'm cancelling" helps too - I dont' say anything like that, but I do genuinely feel it, and it thin that subtly comes across in interactions
I have template messages saved which I send to guests. Yes it is more time consuming but it also opens the lines of communication which is what I"m wanting.
Hope this is of some help.
Cheers