don't they secure that heavy stuff when approaching heavy seas? I mean to have pianos and forklifts flying about like that is downright stupid.

I recall back in my Navy days that we would secure everything before taking off, and then if there was heavy weather in the forecast, we would go about making sure things were secured.

Watching that video, one has to ask, have these folks never been to sea?

As an aside, I also recall one of the funniest things I ever saw on a USN deployment, was embarked Marines being "introduced" to their first case of heavy seas... faces matched uniform color.