Yup, that's me then. No tyre manufacturer would come out and say "Hey, our tyres are ruhbbish when they get low, so change them early!" would they?! Common sense dictates that a tyre with less tread is worse than one with tread. Well, common sense and physics.
With regards to mixed tyres, as long as people read the Sticky thread and understand the potential dynamic changes then that's totally their call and I won't criticise for it any more.