I've read some version of something like this a few times over the last while, and I don't really understand it. You typically vest the option to buy shares, separately; when you leave a company, they may ask you to sign additional agreements. You can just walk out the door, but what they often do is say they will vest all your equity to the end of the vesting schedule if you sign it. I've never done that in my career, and I don't feel bad about leaving money on the table. I was fine with what I had and didn't want additional obligations to the company when I left. This is normal stuff...?