The pin would be open to the intake and exhaust ports. On some engines, that would blow the mixture straight through. Or blow it back out the intake during the exhaust stroke.
Or when open to the intake, it'd probably have a huge blow back, as the mixture would be forced into the hole?
Same with exhaust port. The return wave would blow right into the hole, and that can't be good.
I'm just guessing, but that sounds about right.
Plus you'd have to spin your rings so they don't hang up, and relocating a piston pin is no fun. I just did that on my Lazer. And I'm praying to the moped gods it doesn't come loose.