redishing is simply 'recentering' the hub relative to the wheel. If youve never noticed, a geared hub is offcentered toward port to make room for all those usless gears. SOMETIMES, this offcentering makes for an inadequate chainline (though In my experience, this is USUALLY not the case). If you have a good chainline, redishing is not necessary (though a centered hub is aethetically more appealing to the fashion-conscience).
so you hear all sorts of theories about spinning off the back cog w/out a rear brake. Empricism tells a diffent story. In 17 years i've never done so. And i've never used loctite. And most my wheels do not have a lockring. YMMV. If your worried, run a rear brake. personally, i've never worried.