Huge +1.
When I was going through instructor training, one instructor candidate brought the wrong kind of ammunition for his gun. (9x21 instead of 9x19, or something like that? Can't recall exactly, it's been a few years).
Anyway they loaded the gun up but it jammed up their handgun on the range something fierce - a serious enough jam it could not be cleared by the RSO's. The instructor candidate had to be sent home with a loaded firearm (albeit loaded with the wrong cartridge and partially out of battery, so it was unlikely to fire). This was a tough position to put the TC in, because transporting a loaded firearm, at the time, was a felony under state law; but there was no choice, that cartridge wouldn't come out.
The candidate (predictably) failed the instructor course.
It's the only time I've ever heard of someone failing the NRA instructor training course, and the only instructor candidate that the TC had ever failed, which kind of speaks volumes on it's own. Show up, pay your money, sit through the class, get your certificate, and start teaching. It was a certificate mill, plain and simple. And, more than a little disappointing. At the end of the day everyone gets a gold star and a pat on the back.
The first actual firearms class I ever took was basic pistol - it was a requirement to be able to take the basic pistol instructor course. So I picked a basic pistol class and signed up for it.
The class lasted 4 hours. The instructor handed out a photocopied powerpoint slideshow to folks. (No books). The instructor used the word weapon at least 2 dozen times an hour. The instructor handed out guns to pass around the class, there was no safe direction to point them when they got to you, of course, since there were 25 students in the class sitting at rows of tables. The instructor went on a 30 minute rampage about Diane Feinstein. The instructor had brought his own concealed carry gun in to class (with ammo, he had to unload it), and went on a dialog about concealed carry for about an hour (as the class was also promoted and marketed as Utah and Florida concealed carry class). Then class was dismissed about noon, and we met later that evening at a shooting range.
I was expecting some training, some one on one time, etc. The instructor sat in the corner and handed out targets. Everyone shot 15 rounds to 'qualify' on a concealed carry human silhoette target, then we were sent home.
There was no real training. No practical exercises. No first shots. No coaching of technique. Nothing.
And the kicker?
At the time I had no idea that ANY of that was the polar opposite of how the NRA wanted classes to be taught until I took the instructor course myself.
That was when I raised my concerns about the other instructor, wrote the NRA, and eventually (a year later), after a campaign of complaints that I'd launched, the instructor in question had his NRA credentials revoked, and his IL Concealed Carry instructor credentials revoked.
But, those hundreds of other students he milled through... they had no idea they were getting bad instruction. I shudder to think that it's the only training - or experience with a trainer - that they've ever had, to this day, as most people only do the bare minimum training required to get "whatever" (in this case an out of state CCW permit), and never go back to get any additional training.
Anyway, you get bad apples with every group, but the NRA's "mill 'em all through" attitude towards instructors leaves a bad taste in my mouth.
There are a LOT of people who are teaching concealed carry and firearms instruction who by all rights have no business doing so. They're inherently dangerous, and only doing it to make easy money on the side.