It's rather unreasonable to think that you won't be able to turn off band on router. Especially given fact that 60Ghz is heavily shielded by _doors_, so any usable router would require fallback 2.4/5/6 Ghz connectivity.
Even if Neighbor 2 turns off their router, Neighbor 1 could passively use the radio waves from Neighbor 3's router to surveil reflections from Neighbor 2, including keyboard typing, heartrate/breathing, location and physical activity.
Previous discussion: https://news.ycombinator.com/item?id=27123493
It makes it suddenly ubiquitous when all new WiFi devices use the new standard.
Wrapping my house in tin foil is sounding a lot less conspiracy theorist now! Actually my house is going to be stuccoed - I wonder if they are using a metal mesh that I can ground. Hmm...