here we are
Gleened from these very pages:
http://www.theregister.co.uk/2003/12/04/ms_tightens_ip_grip/
I suspect this is the same cause for legal wranglings with TomTom.
There's no reason your Lights Out embedded linux or whatever environment should HAVE to use FAT, or any other filesystem - it will be the only one using it.
Fileservers though... Fairy 'nuff, in _normal_ operation the internal filesystem shouldn't matter (unless it doesn't support extensible metadata used by the clients).
But, when the fit hits the shan, unless your server is using RAID5, any customer would naturally expect the ability to remove the drives from failed server, and read them using another host machine. You don't want to discover that your precious data is effectively 'encrypted' in some obscure filesystem.
I'm not saying ext3 is obscure, of course I'm just highlighting a flaw in your logical thinking.
That said, I also wouldn't be overly pleased with my "server" using FAT or FAT32. neither of which have particularly robust error correction hashes