A system for preventing unwanted tissue migration in surgical staplers includes a surgical stapler having an end effector including an upper jaw and a lower jaw. A distal end of the upper jaw is connected to a distal end of the lower jaw, and a proximal end of the upper jaw is connected to a proximal end of the lower jaw. First and second tissue stops are formed on the distal and proximal ends of the lower jaw, respectively. The second tissue stop and the proximal end of the upper jaw define a no cut zone when the surgical stapler is in an open position. The surgical stapler also includes a tissue cutting device disposed within the lower jaw for resecting tissue. The system also includes a warning, blocking, impeding, or barrier forming device for preventing the unwanted migration of tissue into the no tissue zone.