macbook pro PAL & NTSC

when exactly did the macbook pro stop being able to watch both pal dvds and ntsc dvds.

Never.

now there is a limit to how many times you can switch before it locks.

This is due to the region encoded on the disk, which is separate from PAL and NTSC, which are formats used for the DVD's video. All bundled DVD drives in Macs use it.

(52652)

If region changes really ever were unlimited, which I doubt, they haven't been for at least the six and a half years since I bought my Powerbook G4 at the beginning of 2004. I was allowed five changes on that one. Never used any of them.

For some older optical drives several years ago, there was an illegal firmware hack that could be applied to defeat region coding. That's probably what you're thinking of. Even though it doesn't work on current drives, telling you what it was and where to find it isn't allowed in these forums.

Blame region coding and region change limits on the movie industry, not on Apple. Apple has to go along with the industry's decrees on this.