I mean, sometimes people don't really care and they have to just adhere to the rules. (Some of those people have already had covid and the vaccines and are at such low risk of spreading it or catching it, the reduction in risk posed by the mask is negligible.) People in the trades, or with similar hobbies tend to have them lying around. Plenty of times I've just grabbed a used up N95 dust mask I had lying in the truck because I had to run to the hardware store really quick and I forgot my more comfortable mask.

More often, it's probably just a lack of training / reading the instructions on how to press-fit the nose bridge.

Then there's people like me with weird faces that fail fit tests no matter how careful with basically everything except the duck masks.