I watched the video and I personally do not support doing what I saw in the video. First I think that pilots underestimate the difficulty of starting an engine with a stopped prop in flight. The engine doesn't like having a 65kt wind stuffed down its throat very much at all so the idea that you can just restart the engine if the approach goes badly may be illusory.
Until recently Transport Canada required that an actual engine shutdown, feathering and restart be demonstrated in flight. I had several instances when the restart process required several attempts with the starter and consumed several minutes. Once the engine simply refused to start and I was forced to do an actual single engine landing
. Fortunately Transport Canada came to its senses and removed this stupid requirement from the ME training requirements.
But the take away for me is if you deliberately stop the prop don't expect you can just give the key a quick twist and the engine will immediately roar back to life every time
Secondly to do a stopped engine glide and then restart the engine on the landing roll and immediately go to full power on a cold engine is a
very very poor practice. You are just begging for cracked cylinders and this sets a terrible example to the student on proper engine handling
