Well, let’s look at previous disasters that befell the NYC area to use that as a crystal ball to predict the future...
Airspace closure - nope, you’re not taking a helicopter off the island unless you’re a public official.
Pier closures - Oh, right, if you’re not taking one of the authorized public ferries, you’re not leaving by water.
Subway closures - Nope, not getting out that way.
Bridge closures - Yep, those are closed too, they might be targets, so you just hunker down where we told you to, right in the middle of the target zone.
Smart businessman who hopefully has his own plan B for shielding all his assets when the SHTF and he can’t deliver any of the promised services that people have been paying him to provide for years. (and anyone care to bet that there’s a rider on the contract that specifically excludes providing services in the event of terrorism, riots or disasters?)
A boat does not necessarily need a pier. Just come close to land and have your VIP jump on.
And have sharp pikes to communicate that ONLY the VIP gets to jump on.
Rich people who worry about this are already pursuing the Warren Buffett strategy. It’s not nearly as hard as it used to be to oversee your business interests from Omaha, Nebraska - or even rural Wyoming.