Tremolo Stabilizer

Just wondering if these things (ex, the link and the tremolo-no in the ultimate FR setup thread) actually work. I mean I was thinking of getting a FR equipped guitar, and if these really do they're job well then I'd definitely invest in one.

The Tremolo no even states you can lock it so the trem is blocked and you can change tunings, is this true? Anyone tried it?
i can't say i've tried it, but i have a damien fr. and i frequently change tunings (dadgad, dgdgbe, open d, c, e) and i just took off the locking nut and still occasionally use the trem. The only issues come when i change strings