and i think 1/2 inch isn't enough movement to worry about Resetting it.
riding it sprung that far isn't a big concern, either.
the main concern is getting it reset in the right place, side wise.

got any Actual source of that idea?
resetting a minor amount of variance of an aluminum frame?
or is it just over-reaction by armchair "engineers"?
how much reset is "too much? 3mm? 5mm? 30mm?
i've reset dropout angles on several aluminum frames. not one problem.
i reset/recentered the rear triangles of a buddie's fuji MTB multiple times(double bends to either side!)... it took five years of his insanity on that bike to create a minor crack at the BB shell... he weighed about 200 lbs at the time, and regularly flung that bike off of major jumps. He SMASHED seat rails into new and creative curves (OUCHY!).. one seat was so badly bent, i was forced to CUT the rails to salvage the post and clamp.
let's hope Clint isn't that crazy.
the unjustifed paranoia about aluminum frames harkens back to the first duralumin frames, and the improper heat treating they endured, and the Way too skinny aluminum Campy cranksets... that paranoia endures, much like the paranoia around tiny finish scratches in the surface epoxy on Carbon Fiber bikes... we see those posts frequently.

there's a pair of trek 3700s floating around this area... i've recabled and rechained them several times now... one got a host of nice upgrades 2 years ago, too.
and the frames both have been reset due to a few hard crashes...
they're fine.
both are 2005 or so models... smalls, in the "Dirt Jumper" frame style.

Road frames are made of a lighter tubing, and they can have problems.. MTBs are stronger for a reason.. i've seen a few Jamises break.. i've seen WAY more new CF bikes do Ugly things, but folks sure buy a lot of new ones, eh?
i've heard several people continually trash talk stout aluminum frames because they AREN'T a fancy brand name... i just talked to a Very high end Ti frame builder that said "all frames, regardless of material, get cold set after the welding is done."
etc.

i think clint's bike will be fine after he cold sets that 15mm away... unless it moves too much, all at once.. THAT is a problem.