the chip has a 'always on WDT' and the only place the dog is kicked is a function where we also set the timer & port registers fresh. if a register freaks out, say the one that has the port direction or the PC, then either the dogkicker will be called (and reset the registers) every 2 seconds OR the chip is completely latched in which case the WDT will reset the chip. same with the BOD, which cuts in at 1.8V (the chip can run down to 1.8V)
however, there is -always- a possibility for cosmic waves, so our design accomdates a pulldown to the fet gate and a 200mA 0.1 polyfuse after the DC jack. all shipping kits have this (we'll update the schem shortly). experimenting with wreaking havoc on the FET and causing a dead-short, the fuse kicks in and 'stabilizes' below the rated DC current for the inductor and FET.
thanks for helping us think about all this again, if you're still reading this send us a note support@adafruit and we'll send you out a kit once we ship the first round of orders out.