I did a show last week and instead of doing the normal rollout from a tape machine I decided to use live shots to end the show. After I faded to black, the video engineer asked me to clear camera 1 tally, so he could turn the CCU off. I informed him I had black on PGM. He believes I had camera 1 online somewhere. So, I took black on ME1 and ME2 both PGM and PST, (ALL keys were off - and Camera 1 was never used as a key during the show) he said the CCU was still showing a tally.
I cleared the tally by cutting to any source other than black. When I cut back to black the CCU tallied again.
Thoughts?