Right, and to a consumer this is all opaque.

You go to a place advertising itself as gluten free / vegan / celiac safe / whatever .. and its been outsourced.

Once it's outsourced, all bets are off. Who knows if the vendor subbed it out further, etc.

Which is why for a certain level of food sensitivity it's almost not worth eating out. It comes down to - do you trust random strangers with your life?