Rusty floor pans

I have a question, can rusty, bad floor pans cause stress fracturing in my front windshield glass? I own a 1970 VW Beetle and was told by someone I paid to fix tree damage (big mistake taking it to a non-VW familiar place) that my crappy floor pans were causing the fracture of my front glass (not true, a rock hit the windshield and someone tore off the rear view mirror that was glued onto it) I formerly owned a 1972 baha that has worse damage to it like around  the door frames and never had this issue.