There have been about 10 times in the last few years when I have walked into a meeting someplace where there wasn't any guest wifi, or we needed the internal network for other reasons.
I can see that this is very much country dependent (we have truly unlimited plans that allow tethering), but at least for me, the smaller size of the machine trumps the ability to plug ethernet cables due to the general lack of available cables to plug.
Why, they don't have the skills to create a private wi-fi network for guests?
I never use guest networks for that exact reason. I know that my traffic and my connection is my own, and works. Way easier imo.