I confesed my fears to Dh last night and he said he could be in charge of the diaper washing. That puts me at ease a little. He may not do it exactly the way I do but he knows how freakishly obsessive I am about so I know he will at least make a good effort.
My MIL has a good heart, and is always wanting to help, but she just doesn't pay attention very well. I can just see her thinking "Oh, this bleach will clean them so much better than that baking soda!" After Dds birth she came over to help out for a few days and I swear she did about 100 loads of laundry. 2 green towels in this load, 2 blue towels in that load, 4 white shirts in another load, 3 white socks in another load. OY VEY!
I do like the idea of putting labels on the off limits products. And I think I will tape my washing instructions to the washer for Dh. I know he thinks I am nuts!