My 5 key is very brightly lit as well.
I did do a brief search; some people in 2009 had a similar issue.
This is likely a build quality issue from the company Apple outsources to. If Apple is at fault it's due to using substandard companies to build their products with.
iFixit noted a problem as well, with the 15" model:
http://www.ifixit.com/Teardown/MacBook-Pro-15-Inch-Unibody-Early-2011-Teardown/4990/2
In short, quality control is something of a fair concern.
Now, not all machines will have problems - this poll reflects as much and "stuff happens". But if, after testing, the only thing wrong with the unit is a brighter glowing light bulb, even if it is distracting, I'd rather be happy with that than to get an exchange and *possibly* end up with a unit with real problems. That can happen...
Apple's uncovered a lot out of these companies they outsource work to, right down to child labor, and I think it's due to passive-aggressive actions on the part of the workers, since a couple of searches has shown a lot of unhappy workers, in very unenviable conditions. I think they should take the next step and find a factory that values its workers and how things are made.