Been over this - some Americans do pronounce it that way, and even if they don't, sometimes it's pronounced that way when you sing because 'er' is more closed and awkward. Hmm, let me see if I can think of an example of Russell Allen himself doing that before PL...
http://www.youtube.com/watch?v=gi7rACkpXwg
The way he says 'lair' in the first verse - 'lai-ah'
And just to show that this is something that occurs regularly based on sounds even in different contexts, you can also hear him omitting the r from 'darkest' right at the beginning so he pronounces it 'dahkest.' But later on, you
can hear the r in 'gather'...why? Because it's not emphasized, he doesn't need to have it quite as open (and even there, I should note, it's still pretty reduced, just not gone altogether).
ANYWAY, the point is I doubt he's trying to sound dumb.