certainly these issues are beyond me
but i recall, when i was becoming frum and would eat only Milchigs in restaurants,
i used to go to a small shack type grill place (not Kosher, at all) near my office and order a grilled cheese sandwich.
i would watch as they would grill up some navaila burgers on this grill (a solid sheet of metal not a grate) then grill up my cheese sandwhich on the same grill. i didnt know this was a problem. they probably grilled some pork products on the same grill as well.
now if i had asked for and received a detailed and complete list of every ingredient in that cheese sandwich, would it have mentioned beef and pork juice and particles?