But what is the reason for the auto extending?
The reason to implement the auto extending was mainly to allow recording without having to manually create the events beforehand. However, I can see your point that if you stop and restart recording at a later time, perhaps the previous event should not be extended, but rather a new event created that will be auto-extended for the duration of the recording. Anyone else have opinions on this?
And will the part in between consume space on my hard drive?
Yes, if a single event covers a section with silence, then the silence is stored in the wave file.