I've done it like Redsy for years, and it actually does do a good job of keeping the strands from fraying, but none of these methods seem like they are positive. I've always used extra care when pushing the device back into the box so that the wire doesn't slip out.
If you hold the device in one hand, and then wiggle and tug on the wire with the other hand, it won't take long before the stranded wire worms its way out from under the screw. You could tug and wiggle all day on a solid wire under a binding screw or a stranded wire on a device with an internal clamp, and it will not work loose.
Matt
