That is one of the funniest poster advertisements I have ever seen. It wouldn't offer the same message though if it said 'I was high on acid, met loads of people who were also tripping balls and had an ace night'.
We should keep this going, what other poster campaigns could they do to stop kids taking acid. I'll go first...
I was high on acid and ended up at a Justin Bieber concert dancing like Bez from the Happy Mondays.