I have two Petzl head torches of a similar but earlier design. They keep getting switched on accidently on my sack. I can't believe they haven't designed this out, especially when the Zoom was such a classic design which always prevented this from happening.
I wish it was still possible to get the old Petzl core.
I rely on the USB rechargability, and love my Tikka XP2, but I broke my old core battery and the new cores don't fit.