I agree with Swine on this one. I feel for your situation in that the car is not in the condition one would expect. However, you mention that they offered to attempt to find the radio problem by having you drive around followed by another XLR and let them know in what areas the reception was poor. You also mention that you don't feel you should have to do that.
Well, newsflash!!!! Not feeling you have to, and having to in order to fix the problem are 2 different things.
It might not be the answer to your problem that you were hoping for, but trust me, the person at the dealer that you tell "I don't feel I should have to do that," is NOT going home at night thinking how much that suggestion (which might be the only way to verify the situation) has incovenienced you. The way I see it, they are willing to do what they need to to solve the problem and by having YOU in the car, YOU can help verify/confirm the problem based on your experience with the car.
My advice, swallow the ego, the pride, the self-importance, and meet them half way. Let them confirm the problem, fix it, and let you and your car move on. I hope it all works out for you in the end.
I wonder if this is the first Cadillac this customer has owned? Why? Maybe they are used to a higher standard of quality control, and the issues they listed are reminders that their previous automobile did not exhibit any of these issues. People have said that the paint problem is typical. This is a quality control issue, and if you've come from a high caliber automobile where the quality control matched the caliber of the automobile, then seeing the crow’s feet would be a big letdown. The XLR should be at a very high level of quality control and quality. Isn't it time that we stopped making excuses for American vehicles and require them to benchmark on their own merit?