Lol, my old puppy was Deefa to.
Its just i saw a lady from my old yard hacking out in a set over the weekend and wondered what others opinions were on it!
Depends which way the bungee is being used - through the bit rings and clipped on to Ds on the side of the girth, like side reins no I wouldn't. Over the poll, through the bit rings and onto a D under the stomach on a stud girth/clipped on to the buckle of a running martingale - yes I have, on youngsters being reschooled out of (big) rearing when hacking. Fitted that way the bungee doesn't come into play unless the horse lifts its head very high and then it acts as a softer restraining reminder than, say, a standing martingale. Personally I don't like standing martingales on rearers as I feel some horses can use them to brace themselves whereas a bungee gives me more flexibility to turn their head and kick on before they get right up and there's nothing for the horse to lean on/pull against other than my hands.
Each to their own I suppose, I know not everyone shares my views about preferred tack/methods.