I think I've posted this picture before -- it's from Steve Portigal's blog, from a post on input device workarounds. This user is obviously not too happy with the touchpad and with accidental contact causing problems. I recently saw a similar "fix" on a laptop belonging to a famous HCI professor. As someone who works at a company that makes touchpads, this is of course a bit embarrassing.
I was reminded of this again by a Lifehacker post about the latest Windows utility someone has written to help with the problem. Called Autohotkey, it disables your touchpad for a short time after you press a key.
Most touchpads in fact do something like this already (not just touchpads from Synaptics but from others as well), but it's obviously not enough. Accidental contact is a hard problem that is only getting worse as touchpads get larger. Not only is it a hard problem to solve, it's a hard problem to measure in a conventional usability test. It's something I've been involved with and hope to write more about here later.
If you're frustrated by your touchpad because of accidental contact, you're welcome to write a comment below or contact me. I'm interested in knowing more about the situations that cause the greatest trouble.