They would certainly appear to simply be mundane, but it's could be reasonable for someone who rolled very high (5+) to see the very minuscule remnants of the magic in their aura, if that's good enough to see the resonance on a technomancer.
Personally I kind of like the impact of a burnout showing no signs of ever being magical, and how painful that would be for some characters and potentially frightening to the PCs (who realize their magic could disappear without a trace). Plus it means they'd have to take the person's word for it or find proof elsewhere.
