I've clamped off decades old flex lines without them splitting, it's low risk. It's actually a brake issue diagnostic method.
But the teeth on them can damage the hose. I have several pair like this I've ground the jaws to a smooth curve specifically for clamping flexible brake lines.

 

Sounds good to me. Besides, if the line was gonna crack, then it needed a new one.

 

I use those too except I put some fuel injector hose (or really any rubber hosing) on the ends.

 

Thanks for all the advice! We made it home safely without incident. Luckily the caliper is just dragging enough to make a racket and wear, but not enough to cause major heat sink. Every time we stopped I'd check the wheel temp by hand, and it was only slightly warmer than the other 3 (however, the rotor looks like ****).

Anyway, new pads, rotors, caliper, and SS flex lines should be at my door tomorrow!