Questions about Vent- & Vacuum Plug

Hi everyone!

I´ve got some questions about the Vent plug (OK-plug) and a photo used for the vacuum plug.
I don´t have any education valuable to say that I know better than any of you guys, but something has recently crossed my mind and I can’t help but to ask.

Have you considered or tried using O-rings on the ´bottom´ of the cap? See photo.
When you screw the plug into the vent, this would force the density of the o-ring to expand, and make a better seal. This would need a slight change in construction of the cap. Am I completely off target here? It makes sense in my head and I’d love to have an open discussion about it.

(Red rectangle shows where they currently are, green circle shows where I´m suggesting a new/extra location)

Also, one of the photos used to show the plug used for vacuum-testing doesn’t make sense to me. The rubber stopper is entered in the hose-end of the plug, not the end that enters a penetrator/vent.
Is this intentional, or an honest mistake? Feels like a joke flying above my head:p

My thought about moving or adding an o-ring also applies to the test-plug.

Would like to point out that all of this is just constructive criticism. I´m completely in love with the brand and it´s features, and would never want to come off wrong!