Western hand saws (not native to North America) do cut on the push stroke; however, a little dust sometimes does appear on your cut line, but I can't see how this device would help in any way. BTW - western saws in no way have less control than a Japanese pull saw - or you've used a cheap or dull saw.
Still, I can't wait to see this lampooned on the woodworking forums. Chris Schwartz will surely have this on his Popular Woodworking blog in 3, 2, 1......