Let's say you're cutting a long green screen project and during editing you forgot to set your target track to something besides V1 so you don't have a lower track to put the green screen background on.
You need to move all the video up at least one track but all the video is Linked to it's audio; how can you move just the video up a track quickly without Unlinking and Relinking the audio?
1. Hit Shift + Z to show the whole Sequence in the Timeline.
2. Hold down Option then click and drag-select just the video portions of the footage.
Holding down Option while you click on Linked footage temporarily Unlinks them. You'll be able to highlight just the video of Linked footage (or audio if you so choose).
3. Now, with just the Video highlighted, let go of the mouse and hit Option + Up Arrow which will move the highlighted video up one video track. Obviously make sure that the track above it is empty.
Now you have your video on V2 (or at least not on V1) and it's still Linked to it's respective audio.