I understand that they are generally "vented", but why such a poor fit? For the batch I bought, the lid and container don't even recognizably go together (like 1/2" difference in diameter). The wind from a box fan could blow the lid off. Even "non-vented" designs appear to have no positive connection between the dish and lid.
Then it looks like the people that do need a positive connection or a seal have to go through a lot of work with tape or wax to seal them.
Seems like a petri dish lid that has a snap, thread, bayonet, or even just friction fit, would be superior. The manufacturing cost differences would be negligible. What am I missing? Thanks!