I believe this is misleading.
The issue I've seen on the older bootloaders is that if the watchdog actually "fires" (causing a watchdog reset),
the bootloader didn't properly clear the watchdog reset state which
ended up causing an infinite watchdog reset loop.
It did not matter when/where the the initial watchdog fired.
This was definitely true in the m168/m328 bootloader..
It was a simple 1 line fix to the bootloader code but the Arduino team never fixed it.
(I patched all my bootloaders)
The optiboot bootloader, which is now used, does not have this issue.
If the bootloader has this issue, it is not possible to use the watchdog timer
beause if the watchdog ever actually occured (causing a watchdog reset),
the sketch would never restart because of the watchdog reset error in the bootloader.
--- bill