Everyone expects there to be a vent in the boards, so the production boards have them.
Personally i am more than happy that a manufacture has managed to produce a board with manufacturing techniques that does require a vent.
Less to go wrong for me anyway.
Sorry, i am unsure of technical details, i was just putting up some gear photos.
As mentioned all Severne production boards do have vents in them, so nothing to worry about guys and girls.