This is what executives with stock based compensations can an usually do.
we only regulate the sell side (or buy side), but not the inaction side (where you hold your existing position). I have not thought of a good way to make the market aware of these choices, in a way that enables market efficiency.
You can then build a statistical arbitrage alpha based on the difference between an ordinary amount of selling (conditioned on a bunch of stuff) and a lack of selling/accelerated selling.
Now if you could see the buying and selling for the next level below them somehow, that would be a great advantage (and also very illegal).
You could probably estimate this if the company has a trading window for employees (which I think almost all of them do).
Sum up the exec sales, then use the previous accounting data to estimate shares held by employees, and then create an index based on what direction employee sales are trending.
Because RSU grants track level (sortof), then you might be able to get a good sense for this, even though there would be lots of noise.
Warning: not investment advice (though if you're taking investment advice from a random HNer then you're probably doomed anyway).