I probably brewed 20+ batches with the day 1 pre-boil, day 2 boil to ferment method- out of necessity (small kids and long brew days). I did get my one and only infection this way. The wort was bubbling away in the kettle when I went to boil the next morning. This was also in the summer and ambient temps were conducive for lacto to get going. I had invested the time, so I actually went ahead, boiled and fermented......tasted awful and had to pitch. So, 95% time (or more), this methodology worked great.