It's also happening as the growing ranges of mushrooms change. You can have a poisonous look alike expand into an area and catch experienced local mushroom hunters that weren't aware of it.

It makes me wonder about the amount of commonality there is in the toxins in mushrooms, and if some quick litmus or chemical sniffing test could be developed.

I remember some years ago I read an article about some Russian tourists in Sweden who got really sick after picking and eating mushrooms. I don’t think any of them died but several of them needed to spend time in the hospital if I remember correctly.

Same thing happened in Slovenia to some illegal migrants who tried to live off the land while making their way further into Europe: they picked up mushrooms that looked a lot like a safe species in their home country but was in fact highly poisonous. I believe at least some died.

The general rule here is that you only ever pick mushroom species somebody has thoroughly introduced you to - books and "I think we ate those at our friends house the other day" are considered quite reckless.