A couple of things I've noticed in Vegas 5:

When I add a music track (to the track below the audio track), if I don't lock both the Audio and Video tracks, the newly added music track throws the Video track out of synch, and I notice a new gap/gaps in the Video track.

Also, when trying to insert a new clip (between two clips), if Auto Ripple IS turned ON, the new clip will cover part of the old clip, rather than just pushing it out of the way to the right (and snapping to the end of the new clip). I though that's what Auto Ripple was supposed to do automatically.