It's not a kick-back, it's a stock sale. If Rand takes a million off the table, he's selling a million bucks in stock (and reducing his ownership accordingly). This actually helps other shareholders a touch in the B round because the company has to issue fewer new shares (causing early investors to get diluted less in the new round).
But yeah-- theoretically an investor could sell broadly crappy terms to some founders by buying out a mess of their shares. If founders want to screw their employees, they can often find a way (see Skype).
I'm not following this logic. If a founder sells their own shares in a B-round and pockets the proceeds -- that doesn't do anything to allow the company to issue fewer new shares because none of the money from those shares went to the company.
Option B: He buys all of his shares from existing shareholders. This requires no additional shares so people who are NOT cashing aren't diluted at all.
I'm just guessing here-- I've never taken money off the table. But I can't imagine it working any other way.