My opinion, which is worth what you paid for it: Long hose SM is only necessary for diving mixed teams, I like to have it for reassurance, but a total gas failure should be probabilistically low enough to be a non issue. If you are sticking to the rule of thirds, you should always have enough gas left in the other cylinder to get yourself out, in fact you have a 50/50 chance depending on which tank failed to have more than enough. There is also the possibility of while air sharing to swap first stages, and to feather. If diving an all sidemount team, the need to actually share gas should be slim to none, could it happen? sure, you also could have every light the dive team is carrying fail simultaneously.... its just unlikely. Also a bit of interest, heinerth and kakuk recommend in their sidemount book that cylinders used in an overhead have the neck orings inspected and replaced on a 6month cycle... which i assume lowers the risk of extrusion further...