It is pretty easy to signal stuff on linkedin without intending to do so. For example whenever I get an old coworker adding me on linkedin, they are 100% of the time job seeking. Inevitably they start a new role some weeks later.

All one has to do is just measure employees linkedin activity. I mean truthfully people don’t use the site at all if they aren’t actively looking for work. It is corporate dystopia otherwise. It is trivial to find these signals.