Is it dangerous to mix hazelnut coffees with normal coffees in stores?

I know of a store that tries to save money by mixing the leftovers of different blends of coffees together, and serving it without warning to customers, and I was wondering if anyone could die from mixing the Hazelnut coffee with the other blends… What if someone had a tree nut allergy? I’ve told the manager and the owner and they say not to bother with it…What do you think?