Your friends are into Pounds per Square inch seminars? Sounds valid to me
Anyhow, just did some quick reading, I don't have an opinion on PSI yet as I've only spent 30 mins reading over lots of opinion posts.
http://www.factnet.org/discus/messag...tml?1183697665
A heated discussion over it, might be worth a read for you if you are concerned about your friends.