FTR, the deep air class ScubaVP refers to is the IANTD "Deep Diver" course. The class has a MAX depth of 130 which isn't what most would think of as deep air. If I understand correctly the use of air (at any depth) or an END > 100 does go against the GUE philosophy, however, this course is usually combined with either Nitrox or Advanced Nitrox.