I have a whip and wanted to point out a few thoughts:
1) I was sweeping a group of riders and noted the bike in front of me had their brake light was flickering on and off in random. Then I noticed that the light was blinking to the rhythm of the whip's flutter in the wind since it was clipped to the front brake lever. After a good chuckle and at the next stop, I had the rider (friend) move it to the clutch. problem solved....sorta. Since this was abnormal to have such a sensitive switch, I suggested she have her brake switch checked. She did and the problem was fixed at the switch.
2) During owning the whip, I also owned 2 types of windscreens. What a difference they made to how the whip flutters. I had the more aerodynamic version first and the whip flew well and never flipped forward to hit me. I since swapped the shield for a flatter version and the whip reacted with a hateful behavior swatting me and flowing rather violently. had to eventually take it off. So, like helmet buffeting, whips will behave very differently depending on windscreens but also fairing wings.
3) I watched a near-miss incident last summer when a group of us were leaving for the road, one of my fellow riders had his foot on the end of the whip; he then pulled ahead turning his bars and that immediately yanked on the front brake (whip was clipped to front brake lever). Well, you all can picture the accident in slow motion: front brake closes on caliper while steering is turned and can't be straightend (because of said whip) and by trying to straighten it up it pulls on the front brake harder...well, gravity took over and shiny side meets asphalt...
So, in my case, lots of lessons learned, not worth it except for cosmetics. More of a hazard rather than a benefit.