Yes you might have a riser wherever the tab ends, so the question is, is that in a part of the blade that's under a lot of stress from riding? His thinking might be that the sides of the blade aren't under as much stress as the centreline since that's where it's bending as you crash over potholes etc. So spread the work across the fork. But when you're braking the tab is being compressed into the fork anyway. It's usually tension that breaks or fatigues metal. You could consider putting it off to the side I guess though if there are no downsides to that. If it means you need to make a spacer to attach the caliper I wouldn't consider that preferable.