Line of sight might be an issue there. I'm thinking more high-end clandestine eavesdropping. Fun fact: curtains are a pretty good defeat for laser microphones, but if the building is really old and made of solid stone, you can point at the rock instead!

The rock?! That’s incredible. I would have guessed it was too dense to pick up normal speaking volume. Then again, even the window glass vibration seems pretty magical to me.