It's a good fix Bird. Shame cars and people got hurt before someone came up with this design. Most likely we wouldn't want to hear all of the flying spring damage and injury reports.
THERE'S NOW EXCUSE FOR DAMAGE/INJURY CAUSED BY OVERHEAD GARAGE DOOR SPRING FAILURES. FOR $4-$5 YOU CAN GET A 25 FOOT SPOOL OF THREADED CABLE @ YOUR LOCAL HOME DEPOT TO MITIGATE THIS POTENTIAL LIFE THREATENING DISASTER!
For those who have wound torsion springs, always replace them in pairs. And they can be up-sized for more cycles. When buying a new door, you can up-size for a reasonable price, and then almost never have a failure.
A little oil on them once in a while will also extend their life.
I had one break as the garage door was opening. Safety tip - never ever enter the garage while the door is moving. That door with one spring gone was really heavy. It slammed right down.
Like you I found that the springs had been installed without a safety wire. They have one now.
By the way, these springs are color coded. Mine are 150 pounds color code 'red'.