"sugar trick"? Sounds strange. I assume that you are using it as an abrasive to remove logo. If so, 600 grit (or maybe higher) sandpaper, easily found at automotive stores or many Wal-Mart's, might be a better, smoother solution.
Why do many people get uncomfortable when someone wants to modify equipment? The cosmetic modifications don't really interest me, but if it makes it more useful to it's owner (speaker sound, light/backlighting on/off, etc.) why sound the "panic" alarm when someone shows off their work? I'm sure each modifier understands and accepts the risks involved. If such "risks" make you uncomfortable, simply don't take them. The panic cry of "you are going to void your warranty!!" is really unnecessary and obvious to most.