This whole thing happened in the late 90s when the camelbak first came out in the army. It was an effective piece of equipment, worked well, but wasnt in line with what the higher ups thought soldiers should look like, so we went through alternating periods of being able to use them and not being able to use them. I think it is a matter of time before the pt shoe policy catches up into the 21st century.
I also like the comment about 3HBCT 3ID. I see Kelley Hill is still its own Army.
Just run outside of PT hours in your civies.