My guess, some p5p person once got bitten by this, and, having its pride hurt, decided it's an outrage perl doesn't protect him from making mistakes - it's better to annoy lots of people than have a single p5p making a mistake. He then supplied a patch, and for some reason, this got accepted.

Luckily, most suggestions for even more warnings never make it all the way into a release. But some do.

Having said that, I do not think this kind of non-portability is quite the same as the Windows vs. non-Windows non-portability. The latter would actually require someone to take the program, and move it to a different platform. The 64-bit vs 32-bit issue can happen because the perl used on the box was replaced.

But I think it's a stupid warning.