That’s a question I’ve never heard. Good.
I don’t see how an eggshell porosity would change in the few days of shipping. The shell is made mostly of calcium carbonate. Calcium carbonate will dissolve in acid, but where is the acid coming from?
Hens that hide nests lay an egg a day until they go broody and quit laying. It’s often two weeks between the first one being laid until incubation starts. Most of these hatch. If something within the egg was causing the egg shell to dissolve, thus increasing porosity, this would not be the case.
Anything is possible but that doesn’t mean it’s necessarily realistic. If you wrap the eggs in something sufficiently acidic (corrosive) for shipping it’s possible, but that is extremely unlikely. I’m not even sure what that could possibly be that a rational person would use.
If the eggs you are receiving through shipping are extra porous, they were almost certainly that porous when they were laid. You can have other problem with shipped eggs, but I really doubt excess porosity would be one of them.