There needs to be a preference to disable volume control with the mouse wheel.
Many times I have paused VLC to check my mail or do something else, and when I resume play I almost blow my speakers because somehow the volume has moved way up.
The control doesn't seem to work correctly anyway:
One would expect the volume to increase when scrolling over the player control window, but that doesn't happen. Instead, the volume increases when not scrolling over the player control window, but over the video itself. WTF?! This too has caused me to blast my speakers because I moved the scroll wheel while watching a video.
VLC 2.0.5
OS X 10.7.5