It sscratched my old DS screen. It will so the same to this. Anyway, it makes the ds look ugly. If you want a strap from a safety perspective since the Lite is very slippery, get one of those white ones that are used for mobile phones. They look much better.
As for the scratching...I'd advise to get a decent screen protector, I used one on my old DS and my screen was safe from scratches. Gonna get one for my DSLite fairly soon....but right now, my DS thumb strap is just there to look kool.
but can't you also order it from liksang-europe? btw: germany charges import taxes too but only for commercial packages worth more than EUR 20 (including shipping), but i assume that's not the case in sweden.