Some of these responses are hilarious to read.
Let's set aside the credibility of the individual trainers here, which a few have questioned. Further, let's set aside the argument of VA Tech for just a second. What is the goal of any, and all training? With each individual move, each movement, each counter-movement, isn't it merely to give you one additional tool in your bag, just one more little piece of knowledge to draw on, in the slim chance that you might get to use it? By the logic of some, perhaps we shouldn't waste our time on ANY training, since techniques can only be useful if they are practiced until your hands bleed, and you become a Chuck Norris Commando.
I use the word "get" on purpose, since each technique involved in martial arts/ weapons retention/ disarming, all require a convergence of unique circumstances, in order for that individual technique to be employed. The more techniques you know, the greater the number of circumstances one of those techniques might be applicable, and the better prepared an individual is in a broader range of scenarios. In other words, if you know a great number of techniques (and you can execute them properly), you'll be more prepared for a variety of confrontations, as opposed to someone who knows few techniques. As Mas Ayoob pointed out, disarming is for when a weapon is presented at close range. The technique isn't applicable, except in specific cases. Obviously, you aren't going to attempt to disarm someone at 15 meters, who is shooting at you. Do you really need to tell a 23-year old woman to RUN LIKE HELL if she's being shot at from across a parking lot? I doubt it. Disarming isn't about teaching someone how to run away. It's about what to do when you are backed into an allyway, (or a classroom) and a crazy shooter has just wiped out your friends, turns the gun on you at 2 feet away, and you have run out of options. As addressed above, such cases happen all too frequently. In such cases, a 10-hour course can give the victim a fighting chance, which is all we can ask from ANY training that falls below the level of professional.
Having said that, there are many, many instances where a close range shooting turns into a grappling match- by default. This is due to the victim's tendency to instinctively reach out, palm out, in a blocking motion. I've seen many videos where someone is getting shot at point-blank range, and the response is almost always the same: An untrained, instinctive, almost pleading hands-out-blocking motion. This is true of all cultures, all people, virtually all body types, with all other things being equal. Of course the blocking motion does absolutely no good, but without any training at all, what can one expect? These poor people have zero chance of surviving, other than to hope for a catastrophic failure in their attacker's weapon.
Disarming technique training- however brief- at least gives someone in this position a fighting chance- however small- to get their hands on the weapon, and interfere with the attacker carrying out his plans. In that moment of grappling, perhaps the defender can take out an eye, or perhaps in the scuffle, the attacker will lose his nerve. Perhaps LE will show up, or maybe someone else in the group will get up their nerve and join in. My point is that no matter how brief, no matter how cursory, a little bit of weapons disarming training is better than absolutely zero, if nothing else than to familiarize someone with the dynamics involved, and remind them that they should stay vigilant and try to avoid these circumstances at all costs.