Alignment won't be a problem, as they will go exactly where the standard footpeg brackets go, so fitting them will mean that you can't fit the standard rider footrests.
You'll have to buy a set of aftermarket rearsets.
But I'm still in, possibly.
I have been thinking about an alternative, where the bracket could be bolted on rather than welded, and by machining 10mm off of the end of each side swinging arm, the plate would fit between the swingarm and the standard footpeg brackets.
The plate can be fitted with 10mm wide bearings, meaning that the bearing could be renewed if any wear occurred, which can't be done if the plate is welded on and without bearings.
Bolting the plates on would mean drilling holes in the frame, but I don't think that this would weaken the frame, and they could be easily plugged if it needed to be removed, unlike welded ones.
Comments welcome, as ever...

It's not falling off, it's an upgrade opportunity.