A piece of fiction:
I was touring up in Mineral Fork of Big Cottonwood yesterday. Never liked it in there - spooky, full of ghosts. Always feel claustrophobic. Know the parable of the scorpion and the frog?
The persistent slab and I talked for a bit on the uptrack. I found ECTX and XPST-60/90. "It's ok, come on into my terrain," she said.
"But I don't trust you, I don't like it." Indeed the powder looked good in Moonlight.
"No, really, " she beckoned - "it's ok, come on in."
I hesitated. Then dropped in. And the slope shattered like a windowpane. "But I thought you said...."
"Sorry. It's just my nature."
Long story short, digging into the snow provides not only information about the snow structure, it offers time to slow down and make collective decisions that have consequences. Snow tests may (as above) provide false stable or false unstable results, but they are only one tool in the toolbox. Many people - after years of being surprised by facets and depth hoar - will avoid steep slopes harboring the weaknesses until spring. Regardless of test results, putting a shovel into the snow will allow an understanding of the structure under one's feet. Sometimes it only takes seeing depth hoar or facets pouring out of a pit wall to pack up the backpack and call it a day. Or season.