Can you really deal certain shareholders out because you don't like them? I was under the impression that there is still a fiduciary duty to non-employee shareholders.
I've seen it happen at least once at a company that I worked for that was sold to Oracle for about $100mm - everyone who stuck around for the liquidation event got retention bonus, plus one of the cofounders who had left (but still had a big chunk of equity) got a "Consulting" bonus - and, of course, the CEO (who had been around for about 18 months) got a monster payoff. Preferred shareholders (who actually had put down $$$) got paid off with a liquidation preference.
100% of the common shareholders, including some early employees who had a reasonable chunk of the company - were totally wiped out. Got nothing for their equity.
I believe this is fairly difficult to prove in court. It happens pretty commonly; it's not super hard to dilute someone out if the company wants to. In fact, it's probably seen as a good move by the board and all current employees.