You can repeat off the students MFD's and switch them to night mode, which makes them go black. The student can just turn their brightness up (if they realize what happened), but it was good for giving them an oh shit moment. The BFI is actually extremely good in the T-6. Pretty much the only thing the PFD has that the BFI doesn't is a CDI. You could fly a PAR off of it in a pinch.