I think this is a false accusation because I have seen Lays wrapper containing local made rings or (pappad) present in the pack and not the real Lays chips. I am talking about early to mid ninties, the reason was simple in Pakistan local companies buy recylced tin foils which are used to make the wrappers just to spend less gain more mentality. So I think this is also something like that case where the foils are coming from some western countries and what ever product inside is local made.
On the other hand these may be coming from the smuggled items from Afghanistan as the American and NATO forces have dogs for searching with them. If this is the case then proper action should be taken against the responsible people.