It is true, the alliance seal is being removed from a/c. It seems as they are delivered new and current planes come out of repainting, the decals are removed. My guess is that the NW/KLM alliance is growing and no longer includes, only KLM and NW, so they're stopping that avenue of advertsing. I would imagine a new logo is in the works and will be something that will include all the member airlines. No official word though, in red tailed land with what's up.
By the way, KLM/NW have had their "act" together far longer than any of the other frilly alliances that have popped up. Remember NW and KLM have pioneered the idea of an alliance and still boast the most fully intergrated alliance in the industry. They may not have a million partners covering the globe, as they are taking their time building meaningful relationships with alliance carriers. It's too bad that Alitalia ditched NW for DL.