@Carl7256 wrote:
obviously the charge is just a night rate
I don't think that is obvious at all. When you stay at a hotel, you also pay a 'nightly rate', but that doesn't mean you can't use your hotel room during the day. I also stayed at a traditional B&B not long ago and, while we were out and about during the day, there was no compulsion for us to be. What happens if, for example, the guest is feeling unwell and needs to rest/recover in their room?
I think, as @Anonymous says, the expectation is that the guest has access to the space from the check in time on day 1 to the check out time on the last day.
I host long term guests as well and it's true that many, many more of them are now working or studying from home, either part or full-time. I can see why it's a concern, especially with the huge hikes in utility bills. So, if it's something that you don't want, then you have to clearly specify it on your listing, but this would perhaps be a difficult rule to enforce.
Or, if you let guests use the kitchen, perhaps you could restrict kitchen access to breakfast and dinner, thereby encouraging guests to go out for a while at lunch time at least. If you have nearby coffee shops where they are happy for people to work (I have one a minute's walk away that a lot of my guests like), maybe recommend those. Again though, it's hard to force guests out of the listing.
Probably a better tactic would be to try to get a clear idea of the guest's plans and schedules before they book and only accept the ones that say they are going to be going to a work place/university etc. full time or at least most days of the week or who plan to be out sightseeing all day. With long term guests, it's good to have a fair amount of correspondence before accepting the booking anyway. I find that guests who are planning to be working from home usually disclose this because they want to know about the WiFi or the desk set up or whatever.