If they don't feet, they don't enter. It totally makes sense. Why do bugs, flies, and mosquitoes enter through insect nets? Maybe because the meshes (netting, 그물망) are not tight. Here's a product which does not allow creatures non grata (초대받지 못한 생물).
The bugging creatures in the advertisements are too big to enter even a window. Tesa conveys its message strongly to us just by changing the objects' size.