There is a variety of large spider that seems to like to nest inside the box tho I’m not sure how it gets in. Smacking the side of the bird house a few times with a stick recommended.

[big spider]

It doesn't need to be small, it just needs to be smaller than your shoe.

...there are usually some in the fold but not in the bag.

I think that's the concern being discussed. There might not be bugs inside the bag very often, but they are nearly always in the fold -- and that's bad enough, because you have to open up the fold in the course of opening the bag.