I also object to any slides that cannot be at least readable printed in black and white. Consider the ink costs - do you think the NSA is made of money?!?
I thought most slides these days print to more 'normal colours'? My university always has slides with dark bgs, images and crazy coloured texts but the PDF slides available to accompany them are always only just the text + any images if they have copyright, and print very well in b&w, if people still feel the need to do that
The need to print in B&W is more about b&w laser vs color ink jets at the consumer level. Quality and TOC is so much better on a B&W laser than paying so much for color ink tanks if you do mostly info doc print outs.