There are large categories of things I don't buy anymore from them now (namely: expensive stuff not manufactured by Amazon themselves) that I know about co-mingling inventory. It's still in the early days of awareness about this, but if they don't change anything, I'm not likely to go back - odds are that it gets worse before it gets better.

I'd be fine with 3rd party sellers if I could simply ignore them. When I can't trust stuff "sold by Amazon" if third parties also sell it, though...