Could be. I also thought possibly when the a/c motors on and off, could make vibrations. Or, if they have sliding glass doors, perhaps that could send vibrations.
Interesting for sure. Ever watch the ex-seal/governors sow on paranormal mysteries? (Forgot his name at the.. JESSE that's it) Anyway he says if he can't see it for himself it isn't real. Interesting to me is other serious folks who do witness something strange and call it fake. Or easily explained by some other way and totally ignore the evidence. In their minds another mystery resolved by them. Then they become expert on the mystery and boor the rest of us to death. Crop circles are a good example of that mindset. What are those skeptics waiting for? A personal visit from aliens or a gazillion dollar investigation to satisfy them personally? That probably will not happen but everyday new facts are being discovered to explain other mysteries. Especially in science. To avoid looking foolish just keep a lower profile until the facts are sorted out. A life lesson I've learned more than once.
BB
