I remember reading something years ago about British Airways not joining the EZed ticket program nor taking paper tickets, thus not being able to non-rev on them. I looked through the Interline section of DeltaNet and couldn't find anything either.

But we would get better deals on Air France anyway, since we have a JV pricing, which is even cheaper than Zed fares. I think between KLM and AF you'd be set anyway, unless BA is the only carrier available for your departure city.