IIRC tape-a-weights are in .25 oz segments, and these look bigger, so I'll guess maybe .5 oz each, so by my count just by what I see on the yellow car is over 5oz, probably much more. And they do not appear to be wheel weights. And I'd hope the adhesive is better to withstand the heat. If they can glue quarter panels on I'm sure they can get decent glue for this. Not sure they did, just saying...
The attached pic from the C5 forum has a pile of weight, maybe 7 or more oz. That's sizable. If a wheel took that much I'd suggest throwing it out.
And I can certainly understand the concept of the added mass dampening some kind of caliper movement that in turn cause pad noise. I can also see how this would not be caught until lots of test cars were rolling and pads started to wear. Hell, it could be brembos fault, we don't know. I understand GM not wanting to tell people they have to wait 4 months more for the SS cars, but I still think they could have handled it better.