This board should NOT be shipped without it being inside an ESD bag.
Unfortunately it is from the "we never have in the past" mindset, as Arduino boards have never shipped with one.
So? That doesn't make it correct procedure. "Because we've always done it that way ..." is the oldest and worst excuse out there.
I'm not really sure I see the point. Practically no one takes ESD precautions when using the board anyway.
Again - so?
The board needs to arrive operational to the customer, you know the person who paid good money for it? What they do with an operational board is then their problem.
There's really no excuse for not shipping the board without an ESD bag. None.