To answer your question...no, it does not worry me. These guys don't play games with their shares (Jed excluded but he's not with Ripple any more).
Plus, I think Chris and Brad have restrictions on selling volumes and timing. I know Jed does so I'm sure they do as well.
Most companies higher execs with significant share allotments have share selling restrictions.
Just like the escrow is managed by smart contracts, and that's 60% of the total supply of XRP.
So, no worries about their shares or the escrow.