Comment 3 for bug 1000431

This is also affected by the cross-fader. If you switch to deck B for like 1 second, then back to A, both tracks get a count increase.

I like method #3, discard the increment if the current track was the last one played on this deck. (To avoid double-counting a track if you're previewing a number of them on this deck and reload the first one you previewed and decide to play it.)