Liquid,
Right from the horses mouth, Tom Mount makes his case for teaching deep air:
http://www.aquanaut.com/bin/mlist/aquanaut/techdiver/display?21954,from
Many people see this and, on the face of it, he seems to make sense. However, when you take a look at the big picture, you'll see the death toll is adding up for deep air divers, and Mount/IANTD/TDI are the examples they are following. In fact, it seems to me that every time you hear about a death, there's no one to give first hand information -- solo or poor buddy skills.
Rather than change the attitudes, text books, and underlying endorsments, IANTD continues down a dangerous path for their students and instructors to follow. Their reasoning is because it's popular and easy to dive deep air, but they are the reason it's popular and easy because they have little to no interest in changing the diving industry and create a safer industry as a whole (IMO).
I wish I could find one of his statements regarding solo cave diving. I'll keep looking.
People can obviously choose to follow whom ever they like. Personally, I choose to follow a different crowd who (IMO) have a better philosophy and track record.
Take care.
Mike
IMO, the only time that having a buddy is more dangerous than not, is if he isn't safe enough to dive with in the first place. In wich case don't dive. IMO, having a GOOD buddy is always safer than solo -- two minds are generally better than one especially if they are of like mind and philosophy.