It's really easy to get "out of phase" like that when you're doing vox-pops or quick stop/start filming. I've sort-of got into the habit of checking the tally-light in the viewfinder but if some of the crew are asking questions, the producer is inexperienced and the soundie isn't even wearing headphones, you find yourself worrying about them when things get a bit hectic, and it's easy to forget your own check-list.

Good point though, I'm thinking about my own ten commandments and that will come into them, probably along the lines of:

"Concentrate on your own job. Let the others cock-up on their own" or suchlike.