One way to tell if the ice is safe, is to walk on the snowmobile tracks. If the track ends, the machine broke through the ice.
I may ask the guys in the parking lot, who are packing up their fishing gear, how deep the ice is.
I also use a walking pole (especially on the lake) if I find an open fish hole, not frozen over I can stick my pole in the water to measure the ice. I like finding at least one foot thick of ice.
If trucks and cars are out on the lake, the ice is safe. I always wear a florescent orange hat. If I fall through the ice, they can find my hat.
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Your post reminds me of a story about ice fishing, a brand new truck, a hapless beautiful dog, and dynamite.
https://www.snopes.com/fact-check/jeep-at-half-the-price/