My clicker stopped working right out of the blue. And so I read stuff here and on the Apple site. Decided to remove the back of the macbook air case... and sure enough, half the battery is slightly puffy. I unscrewed all the screws on the battery, lifted it out (but did not detach it). Checked to see if the clicker worked.
Sure enough it worked fine. Put everything back the way I took it out; and now it works fine.
The batteries can swell when it gets hot. Evenutally this will probably do this again, so in the meantime I'll look for a new battery.
So don't buy that trackpad until you try this.