The real question is, does he really know if they are warmer, or is it just that he's more sensitive to the temperature because he's looking for problems? Over the years one thing that has always remained constant is that customers will always notice something wrong with their vehicles after a big ticket repair that they didn't notice before, even though the issue was there the whole time. It never fails. I remember one lady coming back complaining that she had a tail light out, after we replaced the hydraulic pump in the trunk (convertible top). She hadn't noticed in all the years she'd owned the car that it had one rain light. She only noticed because she was looking for something, anything, that might have been damaged while the car was in the shop.
That being said, I wouldn't doubt if someone did an actual test (not"dude this feels warm") and found that the temps were higher, the question then would be, by how much, and is it enough to matter?
And also warm enough to matter for one person is different than acceptable tolerances for 1 million units shipped where reliability and reputation are one of your most valuable assets (Canon and Nikon professional cameras vs Sony/Pentax)