To give some thought to the reasons for jumpers, there are some simple reasons. And yes, some fish will jump no matter what you do.
I think the majority of fishy-cide by jumping is caused by photo-shock. I think in most cases, folks have their lights simply come on full strength at a certain point in the day either manually or via a timer.
If you've spent any time on the SW side of the hobby, you may have noticed that there are a whole boatload of moonlight simulation vehicles out there now. Since that side of the hobby has evolved to emulate natural cycles more and more over the last 15 years, the FW side hasn't paid quite as much attention to the effects of lighting cycles on fish and other organisms.
What I'm inching my way towards here is the notion that lighting should be brought to full strength in steps, wherever possible. I use blue actinic lighting to get the fish in the fish room up and about for breakfast (I'm out the door early!). Just a simple bare flourescent fixture that doesn't have to come close to covering the length of the tank. There's no jitters, no dashing around, nobody looking dazed and confused and best of all no jumpers. They adjust to it calmly over the first half hour and are ready and raring for breakfast before I leave the house. The timer is set to go off once the daylights come on. Conversely, the opposite works just as well before lights out at night.
It's not expensive. As an example, I have a simple 2 foot flourescent strip light over a bank of 3 20G's on a simple timer. About a $30 investment for everything. The limited hours on the bulb will give a service life of anywhere from 3 to 4 years. Remember it's not intended to grow plants. There are tiny and inexpensive fixtures made for nanos that will serve the same purpose.
Will it stop 100% of jumpers? Absolutely not. There's lots of reasons for it. But photo-shock is just one that has a pretty simple fix. If they don't jump, some fish just smash into things in that first second, causing a whole different set of issues from the fishy-cide leap.