That warning sign might make her not open the jar recklessly in the future! We wan't sneezes don't we?
Well, this sign can be ridiculously small and hard to notice (like some comedy use of «fine print»), so the ponies will continue to recklessly open it.
Also, since I mentioned some signs...
Do you remember that Soda medal (made from APD’s drawing
) from... uhm... 2020 or 2021?
The sneezy warning signs may be designed in that fashion
.