@France-Marie0 While most guests assume these days that there will be Wifi, it's not something written in stone-you just have to be very clear in your listing, as well as in a message to guests when they request to book (I wouldn't use IB if I had this situation, as guests often don't read much in the listing, just look at the photos and the price and IB).
I don't know how ethernet works (am techie-challenged) but I do have cell-based internet at my place. It is metered, so not an unlimited GB situation, but I can buy more GBs as needed. The way mine works is that I have a separate phone with a tethering capability, so when I turn the phone on and open that setting, I or a guest, once given the code, can access the signal either on their phone or a laptop or tablet. Unless someone is actively using it, that phone is turned off, so not emitting any EMF. That phone gets left in my home, where I list a private room, so if I'm out, or gone to bed, the guest can turn it on themselves if they need to get a Wifi signal.You can get an inexpensive phone for this- doesn't matter if it has a crappy camera, or anything else, just as long as it has the Hotspot/tethering feature, which most phones do these days. There are also actual modems available where I live for this cell-based internet, but then the modem would have to be turned off if you didn't want it emitting a signal, which might be more involved than shutting off the phone.
I am very clear in my ad that internet is limited- no Netflix, streaming, uploading large files, or working online all day, but fine for checking email and surfing the net a bit. Also I reinterate when they ask to book. My guests haven't had an issue with it. A few have used a lot of GB, but others hardly any, so it's balanced out.
I have had a guest who is very sensitive to EMF, but she still uses a phone and emails if absolutely necessary, as it's hard to avoid in this day and age. But at least now she knows what that weird feeling in her arms is, that went undiagnosed for years. And I also had a guest who monitors EMF in homes and businesses for a living. He told me even electric light does things to our brains that aren't so great.
As you are going for the full meal deal on EMF-free, I'd advertise as such- make that one of the main selling points, even using it in your listing heading- that way it will attract those who are looking for that and won't make some fuss because they can't watch Netflix or work online all day. And play up in the listing description the fact that you are a naturopath and that your family lives a healthy, natural lifestyle.
And if there are cafes nearby where guests can hook up if they need more Wifi, have a list of places and directions for the guests.
BTW, I wasn't sure what "amenity" option to check for cell-based internet, so at first I just checked the WIFI unlimited, but explained the system in my listing info. I've since changed it to "Pocket Wifi", as a tech-savvy guest told me that would be be the closest match.