Obviously only when using EasyBCD to boot into Windows.
I realize in this particular case, he has Vista on the same drive as XP, so obviously the one controlling the boot on that drive (drive 0) is most certainly Vista, meaning it would
be safe for him to run the command...as long as he is not using any 3rd party bootloaders.
But what about in a situation where someone has Vista on one drive, and XP on another, and he wanted to get into XP by changing the boot sequence to put the XP drive first? If he ran the command to put Vista's bootsector on all
partitions, wouldn't it make XP unbootable that way? I just think it would be safer to tell people to put the Vista bootsector on only partitions that contain a Vista OS.
But then again, maybe I have that wrong, and using the "all" command will only put Vista's bootsector on the drive you're running it from, and not on all