Clearing videotape?

I don't think it makes any difference WHAT you record? If you record black, the logical conclusion most people will draw is that the tape is blank and it has continuous timecode with no breaks. Even if you skip a frame or two when recording clips on that tape, the timecode will still be good and the black will act as a good transition between scenes.

Just the act of recording anything on the tape will erase what was there before. Black just has fewer drawbacks if you don't get your new clips touching each other the next time you record on that tape.