I don't think the idea of subliminal images in WTBTS drawings is far-fetched. It was quite a controversial topic in advertising back in the 70s and 80s. The WTS would certainly not be above using such manipulation. If I'm correct, this type of advertising is now considered ineffective (not to mention illegal), but that's not the issue here.
And CoCo, I seem to recall that someone here on the board did claim to have been in their art department, and says it was never done, but well, what-EVER! This is no court, and if it was, well, you have 'expert testmony'. Nuff said.