Well it was a good idea in theory...

Mother: Mister Rain's falling so you're not allowed to go out!!
Ko: yu-n
Ko: Myamya... Shabe Mwe.... I'm so sorry...

actually,
"must not go out"
would probably convey a better meaning

This is why this idea never panned out and died away quickly.

I always thought the Marisa in the bag had the superior idea.

Except for the suffocation and the fact that water goes right through plastic.

what kind of water goes through plastic? o_O

Rain. Haven't you ever seen a drenched plastic bag out in the rain? Completely soaked through.