This makes no sense, the GC does not apply to terrorists (Al Qaeda detainees) even when captured by a Convention signatory (the US).It would seem that the Bush administration feels that it can suspend the Geneva convention agreements with respect to prisoner treatment, in the case of Al Qaeda detainees.
The GC covers several things, among them treatment of enemy forces upon capture. Under the basic rules, mutuality is a condition (so whatever the enemy does to yours can be reasonably done to theirs). There have been a number of amendments and improvements to the GC since its inception and in the IVth Protocol they added provisions to cover enemy combatants out of uniform, but the US never signed on to this.
The US (and several other governments) would not ratify the IVth Protocol because it was deemed to endanger another of the GC's concerns; civilians. The Protocol, in any case, would apply only to those who, lacking uniforms, sported some sort of distictive identifiable insignia of an entity with some sort of hierarchical structure, with an identifiable chain of command wherein the individual captive could be situated.
The only constraints on how Al Qaeda members captured can be handled are those their captors choose to impose on themselves.
There are some advantages to treating the terrorist detainees miserably; it could help in extracting information, maybe encourage new captives to spill the beans in order to avoid the troubles their colleagues endured; it could discourage the more weak-hearted from setting off to the madrassas if they anticipated they could get caught and humiliated being photographed wearing panties on their heads with enemy females laughing and pointing at their genitals; it could even provoke riskier terrorist ventures in retaliation and they are having a tremendous casualty rate among their own with each attack so this helps reduce their number.