Well from once sticking up for Liebing before on this forum when people were having a pop at him, I've now noticed how little credit he deserves for the sound he apparantly developed, and you just need to listen to any Andre Walter 12" to hear it. I could imagine some of the guys we're talking about doing collabs with Eric Morillo if it got them further up that ladder, sad but true I think.
In saying this I've interviewed Liebing and Bailey and asked them about this before, and neither of them hide the fact that they use a co-producer, in fact Liebing did credit Walter as the main force of the Stigmata releases. Bailey does maintain that he has the biggest input into the tune writing, but says that Hades and Redhead are handier in the studio than him. While these ghost producers may be happy to hide in the background it's not particularly admirable that someone else is taking all the credit. That said, this is no new phenomenon in techno. Loads of producers have used engineers or co-producers in the past... DJ Hell is an obvious example.