Brent must be the luckiest guy in the windshield repair industry, lol.
I have had more than one w/s crack out just by removing ice and snow off the w/s, starting the car and running the defrost. I can recall this happening a couple of times anyway... cracked before I ever touched the chip.
I have also cracked a w/s using a hair dryer. I remember thinking how it was a great idea because it had to be a safer method than using higher temps like a torch or cig lighter (drystar). I just had to be patient... but I was horrified to see it snap clear across the w/s. It's funny now... not so much at the time.
I've used various propane torches (the big ones, not a mini) for the past several years (6-8??) without much issue. Only time I have had a problem, I was doing stuff I shouldn't have... experimenting. LOL...