...I don't really get why this is an argument.
If you believe you're pregnant - shouldn't you be going to the doctor anyhow?
Why bother sitting at home starring at a pee stick hoping an evap line pops up?
Looking at the fact that those tests aren't even 100% accurate most of the time (they can be taken wrong, etc, etc.), there's a reason the boxes say invalid after such and such time.
If you're pregnant, you'll notice eventually with or without the test.