The way I learned, and how we teach is by holding the hose. If donating in an OOA situation and you palm the regulator 2 things come to mind. [thing 1]=If you are palming your regulator, and I am OOA and stressed, it would be very easy for me to jerk the whole thing away from you, and hopefully you can get to your secondary. [thing 2]= I am palming the regulator to give to you because you are OOA for whatever reason. You aren't familiar enough with my equiptment to know that the regulator can be cleared without pushing the purge, which just happens to be under my palm at the time, and you freak out even more. We teach/train this everytime, because statistics show that in a "stress" situation tou revert to whatever you have been trained to do. Whether or not it is acutall training or just a habit, you will revert to whatever or however you commonly do thing. Also while holding the hose you have a much firmer grip and make it much harder for someone to "take away" the whole thing. Just my 2 cents.