Agreed. That wouldn't be an issue for households that already stream as they have already needed to deal with that. Of the remainder that are non streamers, any, where the modem/router or router is located reasonably nearby will be ok. These last ones past that will need to be handheld to get a Chromecast connected and wifi if any issues, and be assisted with. The demographic here should be pretty small, Rugby fans who dont want to know about the internet. I would expect that many non IT literate older people have a tablet and that also bridges the gap quite well, as that becomes the RWC device, albeit preferable to cast it to the telly
The issue I could see, is that these people need to sort this out before the RWC, not the day before. Maybe there might be pre coverage of older RWC matches that newbies can work through the setup with