I'll take your word for it...but all the ebay sellers keep saying "International buyer (non US/Canada/America) please beware of the game's format indicated on the game description" (which is format 2:NTSC)...I don't get it...
NTSC doesn't even apply to portable screens. It's a format for TVs. NTSC format is used in most of the Americas (other than Brazil, Argentina and a few more), Japan, South Korea, Taiwan and probably some other countries. Basically, that means that as long as your player can read them, DVDs, VHS movies, TV video games, etc. will play on any TV from any of those countries I mentioned.
The other popular TV format is PAL. That covers places like Europe, Australia, Brazil, etc. Historically, PAL format media didn't work on NTSC TVs and vice-versa. Nowadays, newer TVs can display media from either format.
This is completely different from region-coding. If a movie or PS2 game, for example, is coded for the Japanese region, it will not work in an Australian PS2 or DVD player. The DVD drive only allows movies from the same region to work. On the other hand, the PS3, for example, is not region-coded. ANY game from any region will work on it. The DS is also region-free. ANY DS game will work on ANY DS. Things like NTSC and PAL
do not apply to the DS. The DS is not a TV.
The warning that you are seeing on E-Bay is just a general warning that's given to all games, regardless of whether is actually applies to them or not.