I have an NTSC chipped console and a PAL TV. PAL backups put PAL signal out the back and NTSC Jap originals and backups put NTSC out the back. Because I have a PAL TV, I have placed an NTSC-2-PAL convertor between the PS2 and the TV which I use when playing NTSC games.

So, if you have a PAL/NTSC TV, then subject to the way in which that TV switches, you shouldn't have any worries, won't need a convertor and your SCART cable should work fine.

What puzzles me is why you're asking? Doesn't it work?