When swapping out a closet light fixture this morning, I found that they had attached it by stripping a small section of each of the black and white wires and bending them around the appropriate screw. The wires then continued another 2-3 inches to the wire nut for connecting to other circuits.
Now, I've removed this mostly because the way the screws were on my new fixture made it a serious PITA to do it again, but I'm wondering if it was ever OK or not.
I removed it by cutting the wire at the strip point, adding that to the bundle in the wire nut, and adding a 2-inch piece of wire appropriately stripped from the wire nut to the fixture. And I did twist the wire bundle before screwing on the wire nut.
The house was built around 1967 or so, if that helps, and wire is copper.