Coincidentally, we did add an extra key for this in the 2008 version--but only for skipping questionnaires or for ending the experiment. From the guide:
In previous versions, the combination Alt + Right Arrow would end the current questionnaire or file. Because this combination is now commonly used in web browsing we added a shift key to the combination to avoid accidental endings.
Honestly, I didn't even know you could use ctrl+right (or left) to skip words. If that's the case, then that would certainly make sense to provide an option to disable the secret keys. Will put this on the to-do list for the next version. In the mean time, a couple possible work arounds would be
download and install a shareware keyboard mapping program that will allow you to disable the ctrl and/or arrow keys, or
put tape over or physically remove the control keys for these sessions. And yes, I apologize for how silly the last suggestion sounds but to be honest, that's probably the quickest work-around aside from installing a re-mapping utility.