... to follow myself up...

I went ahead and looked in my .vimrc and lo and behold there's a "security issue" in it:

    if $USER != 'root'              " Modelines let you specify format rules for a file within the file
        set modeline modelines=5    "   e.g. "// vim: tabstop=20 : shiftwidth=20" (or something actually reasonable)
    else                            "   They can be a security vulnerability (unlikely) so we don't enable for root
        set nomodeline
    endif

... so yeah... I guess there's some concepts worth being extra sensitive about... but even still, surely y'all can handle this stuff.