Frozen baseboard heating pipe

A couple of years ago during a particularly cold winter came home to a garage full of water. Turned out the original hot water baseboard heating pipe for the top floor had about 8 feet between rooms run through an unheated attic space with no pipe insulation . Haven't had a problem since (it's insulated now!) but I do get nervous on cold days. I was thinking about running a length of heating cable, perhaps on spacers to avoid direct contact, but wonder if this is an acceptable application.

Insulation doesn't 'make' heat, it only slows the transfer from the hotter area to the colder area. If it was that cold, I'd expect that zone would have been calling for heat, and it shouldn't have happened. But, if you shut it off, or turn it down at night, it could. If the line runs close to the ceiling and there's insulation above it, as long as the room below was heated, it should not happen. Many heat tapes should not be installed in insulation...you'd have to read the instructions carefully to see if it was an allowed application.