If I take a weight low enough so that I can do repeated doubles with it, I can make large technical errors and still muscle up the lift.In the snatch I can not keep it close off the floor, swing it out in a big loop and catch it easily. In the jerk I can drive the bar forward and catch it.I see lifters practicing and ingraining faults all the time in my gym by using a light weight which they can manhandle. So be careful.