i did just that a week ago. Thinking fuck it , Im going to drive alone and watch Mt Fuji. Even stopped at an hotel with higaeri onsen ok.
There was no other car on their parking lot so I thought. Yay, i will have the onsen all for myself, (and it haw views on the Fuji!)
... which was true until a muscular yakuza with a superb dragon tattoo on his back came
We didn’t talk, just a weirdo overweight French guy and a yakuza naked (at 3m from each other) , butts in hot water, watching this symbol of Japanese purity and esthetism... it was surreal