If anybody doesn't think this is a problem, I overheard managers talking about a 3rd-party tool that finds "at risk employees" which they didn't define but said it included signals such as "they updated their linked in recently" as a signal that they may be on the job hunt. You better believe that data brokers are both interested in buying and selling any sort of information around your employment/job/interview behav…
I've seen similar insights, derived from a person's social-graph through email exchanges, and it was decided to not be used by managers as it could be a liability.