Smoke alarms might not protect your kids because kids sleep differently than adults do. Here's a brief video explaining what that means for your kids' safety and what you can do to make their odds of surviving a fire better.
While the video does not deal with the haredi community specifically, it's important to add that leaving a hotplate, even when UL listed, on and unattended for any period of time, let alone for 25 hours over Shabbat, is very dangerous and should not be done. The same is true for leaving a gas stove on and unattended, even when there is a blech in place, and for doing the same with electric stoves, as well.
[Hat Tip: Seymour.]