I have had three parties contact me to stay, all the interactions had an element of oddness to them.
One person said he had a medical condition, so he changed the direction he was traveling. Not sure how that helped, since he was now camping, but the bottom line was that he didn't bother to call me to tell me. I discovered this when I called his cell phone on the day he was supposed to arrive. Not nice.
The same kind of thing occurred for another party, in which they folks just didn't know whether they were really coming, as, perhaps, they would do something different. But again, no contact to inform the host that it wasn't happening.
The last party was not inconsiderate, but they called for the next night and we were out of town that week. It's not a problem for me that guests might choose to contact me at the last minute. If I am able to host them, I will. If it's not possible, or just too inconvenient to accommodate their arrival at that time, that's something they just accept.
But listen... If you're on a multiple-day journey and you've got a commitment from someone to host you, they're assuming you'll be coming, are no doubt reserving time to share with you, introduce you to the area, perhaps planning a meal for you, and so on. It's just not good form to leave them hanging. So be clear about any uncertainty you might have in your plans, and agree on what will work for both parties regarding updates, change of plans, and method of communication.