I brought my MacBook Pro in for servicing today. Some of my keyboard keys got sticky. It started with the Tab-key 2 weeks ago. For several days I had to press the tab very hard in order for it to work. Then all of a sudden it worked again. However, over the weekend the T-key was aching up. Oh, and in between the J key was not always working either.
Looks like it is not an too uncommon problem:
And, I never spilled anything over the keyboard. The friendly person at the Apple Store asked that question real hard...Let's hope they fix it and I that I get my machine back sooon.