No. That's the entire point. As the other poster said, Owsley was the first large scale producer of LSD. Obvious risk of what? Up until then, the risks you're talking about didn't even exist, let alone being common knowledge.
I read that book as well and it was pretty clear they wanted people to take it without exactly knowing what they were getting into; at least, it escalated to that point. They being Ken Kesey and his group more so than the Dead. One of the core bus riders eventually quit because he saw it as non consensual dosing. That was my takeaway anyway - there is a good amount of ambiguity in the way the book is written.
Are you talking about the party-goers or the organizers. The attendees did not have a good idea of what they were getting into. The organizers were comically amateur-ish.
