aside from the initial orientation, any owners would then also need to carefully remember which orientation the filters are fitted.
Any subsequent removal (by owner or garage to fit other parts etc) would then need to ensure they are re-fitted that way.
There is potential to refit them differently, with the dirty side then on the filtered engine side.
from what I can see if I was a twintake owner , Id be marking them in some way (based on which ever way Id fitted them)
^^^^ A very important point, John
The filter cannister ends are already clearly marked with moulded arrows. All you have to remember is your own interpretation of them: For me, and originally Forge UK but not Forge USA, the arrow very logically indicated the direction of air flow - i.e. arrow points inwards to show that air flows inwards (now officially deemed by Forge worldwide to be the 'incorrect' but non-damaging orientation).
It's now academic but the arrow does beg the question of how else can it indicate anything other than the direction of air flow! Arrow pointing into the filter centre = air flow into the filter centre..... But, no, now it doesn't
This is the arrow moulded on other end:
Hopefully, Forge will have learnt a lesson from all this but it's not helped by there now being as long as 8 weeks delay on Twintake orders. The funny thing is that if I didn't already have a Twintake, I'd still wait for one - I love it! They say that's the definition of 'love': You love someone/something
in spite of their faults. So I continue wearing my Forge hat with pride.
As with any component when it's removed and re-installed, there is the potential to re-fit incorrectly. It's a matter of either very specifically briefing your mechanic or being present (which I usually am).