I'm not a cave diver, so correct me if I'm wrong, but i believe that the 7' hose was designed for single file exit of an air sharing buddy team from a cave. Some people feel that if you aren't likely to have to do that, then 7' is too much and just use 5'. I have no interest in the wet rocks myself, but I use 7'. You do need something on your right hip to route it around if you aren't carrying a can light, but these
things work well or you can make your own.
I like the idea of being able to put plenty of distance between me and whatever is happening at the other end of that hose, even if I eventually have to get behind that diver and control the situation. One of the reasons why I don't like a conventional short octopus or one of those Air II things.
And as was mentioned upthread, it's best to have this discussion with your buddy ahead of time, especially if he or she is an octopus fan. From what I have read, in real panic situations, the inadvertent freediver on your team may well head straight for your primary anyway, so plan A might as well be letting them have it.