OK, I'll ask - why not just avoid pressing that key combination?
Oh - and I found this in about 30 seconds: Adobe Lightroom - Remapping Keyboard Shortcuts - won't this work for Lr 4?
Added: This within a minute: Keyboard Tamer - Make Adobe Lightroom work for you by specifying your own keyboard shortcuts
It can't be done in Lightroom - Adobe hasn't implemented keyboard remapping.
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Yes, it is...