You would hear a noise or the movement would be pretty noticeable, especially if it was causing wall damage.

I'm already seeing some aggressive movement on pricing of multi-family due to sellers buying poorly a few years back or are anxious to liquidate.

Some are starting to show signs of movement/ foundation sinking.  

Dual signatory restricts the movement of funds without your specific signature (the IRS agrees that this does not rise to the level of constructive receipt by you.  

The movement from the Cities like San Francisco , Oakland and other larger metro-areas has a lot to do with the reasons people move to those areas in the first place. 

The foundation is block and was spilt and filled in, but not repaired to prevent further movement. 

The house clearly had some "settling", the price was low for the market, and the house was 50+ years old, so even though there was clearly some foundation movement "in the past", it was a solid purchase. 

There should be a lobby for some type of movement. 

Heck look at the recent movement in the stock market, it was a small trough in late 2018, and like you said the investors came in and bought, stabilizing things and bringing it back quickly.

I'd go further to also lump folks who buy properties to make money on "rapid appreciation" (like a property increasing in value 50% in a year w/ no improvements) in with that group - most have NO understanding of all of the market forces that cause these movements and no clue how to actually analyze the market .Even the experts who have substantial education and work for multi-billion $ firms don't predict major market disruptions (in either direction).