You are so right! Testing is truly the key to success.
I do have a process of generating EAs once a month only because I have limited resources (time and computer) to run them daily. But it also coincides with my rule on demoing first.
I actually did use the Validator tool on the EAs that I get from Petko in my courses. If the EA passes the criteria that I deemed acceptable, then I go live with it. For instance, the EA from Petko was ran through the Validator that has already been uploaded with the current historical data (I do this once a month as well). AS long as there are at least 10 trades and my other criteria is fit, then these are the only EAs that I go directly into live trading. I still put them on my demo account as well, just to keep things in sync with how I handle my automated trading.