It shouldn't be frowned upon. It's just a sudden urge of emotion (usually bad unfortunately) and I think in most cases it really can't be helped, just happens. Although I'm sure there are some who add it for dramatic effect.
I would think it maybe has something to do with the adrenaline rush from the shock?
It has only happened to me once, when my husband had an epileptic fit and lost 2 years of his memory. The shock just over came me.