No, not the American flag! The damn training flag that has become so prevalent in recent years! 
Like whips and spurs and bits, the flag can be used correctly. It is particularly useful in convincing a mustang that he does not want to jump over a panel despite the fact that you're standing in front of it. :-) I can also understand its use to dissuade a horse who is trying to run over you or one that stubbornly refuses to move away from other kinds of pressure. But I have to say, it is also the most misused training tool I have ever seen (along with being one of the most overpriced!)
Before you could buy a Sooper Speshul (insert NH Trainer du Jour) Flag, people simply tied plastic bags from the grocery store to their longe whips. Never mind that the longe whip, as a longe whip, had been doing a fine job for many years without accessorizing. Now the longe whip not only cracked, it snapped and popped. Otherwise sane horses bolted away madly in fear at the white snapping-cracking-popping thing. We started to see horses who spooked at carrot bags and seemed traumatized by any form of plastic. (Did I mention the Sooper Special flag shown here will set you back $44.95? No, I am not kidding. For something you could make out of elements purchased in the damn dollar store.)
I was still in Los Angeles when I saw my first NH trainer. Now, being L.A., we had our share of characters to begin with. We had a Parelli-trained Shire who could only be ridden in a rope halter and had never learned to wear a bit, we had a clicker training aficionado whose horses would lope a total of once around the arena before slamming on the brakes and turning their heads to her knee, looking for a treat, and we had a poor little yearling mustang in training with a guy who billed himself as a Natural Horsemanship trainer. NH guy would take little mustang to the arena and flag the bejeezus out of him. If the horse dared to come to him, it was sent away with much grocery-bag shaking and theatrics. The horse looked scared and confused. He couldn't figure out what he was supposed to do and watching this display, neither could I. He wound up going home to live at his owner's - still not even vaguely halter broke, but with a newly acquired plastic bag phobia.
Since then I have seen people flag, flag, flag away - not just at the pushy horses who won't move away from pressure, where it makes sense to escalate to something bigger/noisier than a whip - but at baby horses, scared horses, confused horses and horses who aren't doing anything wrong at all. I always think it's interesting that a lot of NH folks want their horse to ignore a tarp whether it's under their feet or draped over their head but then they take a flag, which sounds just exactly like a little piece of tarp, and that's supposed to make the horse move away. Gosh, I'd be confused TOO!
Heck, it isn't even consistent that the horse is supposed to move away from the flag. Here's a video bragging about the horse's ability to ignore the flag. Ooookay. Now what does she move away from? Nothing short of a small nuclear explosion?
Yes, the confusion continues:
Use the flag to desensitize!
No! Use the flag to scare the horse away if he's aggressive at feeding time!
No! Use it to desensitize the horse not to kick!
No! Use the flag to exaggerate the pressure you're putting on the horse!
Poor horses, I'd be confused too. But there's just something about the flag where it's practically sacred to these folks. I just read the silliest trailer loading article ever where it cautions against using any kind of butt rope or whip or anything to load a horse because you might create a "fear memory" that makes him not load (for the record, total hooey. I have taught many horses to load with a butt rope and a whip and they have learned to be good loaders with no problems). In the same article, we're told to use a flag: "The shaking, rattling plastic will be an aversive stimulus to the horse and it will scare him. He will quickly learn that he can make the scary thing go away by moving forward and that he can avoid it altogether by not moving back. " Uh, this is the EXACT SAME THING I can accomplish with a whip. But that won't cost me $44.95! Or $62.95 if it's a bigger NH name! Good LORD, no wonder they all have such pretty horse trailers!
Let me introduce you to a friend of mine. We call him Mr. Whip. He costs $7.95. He can be used to make a noise just like the flag - it's just that it's a whipping noise. He can be used to give a horse who won't move away from pressure a little sting to get his attention. Mr. Whip cannot be abusive on his own. As long as the person handling him has some self control and good judgment, Mr. Whip is a very effective training tool that is not "mean." You can even get him in bright, primary colors (although you risk a traditionalist beating you to death with your own lime green whip if you do that - don't say I didn't warn you.) The colors are for you, anyway - nobody knows if horses even see color. Retailers are just hoping the person with the checkbook is easily distracted by brightly colored objects.
If they're going to cost that much, may I suggest a Vuitton print?
