This is fantastic. Thank you for writing this out. I have to be honest, I thought aerial imagery was basically a live feed of reality. It never even occurred to me that it could be outdated, or that crucial information might exist on things called "traffic signs" on the actual ground.
Your breakdown of "facts" (from signs) versus "assumptions" (from old pictures) is a complete game-changer for me. I'm saving this as my new guide. It’s a whole new world of mapping now. I can’t thank you enough for this wisdom.
All the best ;D