Driving over something that tips the tractor, something unseen, like an animal hole, makes any tilt-o-meter useless. Because that 15deg goes to 25 in a split second. I had a situation the other day. Out in the pasture, knee high grass, ran over a hole, oh how nice, who put that pos there. 40yrs earlier there was an old oak, now a decayed stump, and divot from the blow over. The memory of that is so long gone. It looks like a grassy field, the same as it has for decades. Some of this stuff catches a guy off guard, and there you go. Drive slow and deliberate, situational awareness, stay vigilant and don't let your gaurd down.