I'd say it's more of a security problem with NTFS than their
protected-mode blah blah blah stuff. Windows need Himem.sys anyway, so a
DOS kernel with built-in XMS Manager and NTFS wouldn't be too weird.
(Apart from not able to run some real-mode only DOS games...).
But imagine your "secure" data in your home dir under NT being readable by
everybody than boots up this DOS kernel...
And yes, I've heard about the "physical security" arguments... But a
multi-boot NT and DOS (and Linux) machine is not rare.
Stephen