A half check collar is just a training tool and any tool can be misused and/or abused. I don't have issues with half check collars as long as they are used appropriately. I don't ever think it's appropriate to use them on a puppy.
A dog should never be corrected for things it doesn't understand are expected of it and of course a puppy doesn't know better. This is the age when you're teaching behaviors and making it fun for them. Proofing behaviors comes much later down the road.
Any good trainer would never recommend something as a fix all solution. Every dog is different and every situation is different so feel free to ignore their recommendation and find other ways that work better for you and your dog.
I don't know if this is true, but I was told by a dog trainer that was very high up in the met police's training team that half check's were a huge money making swindle and didn't do anything.. but were designed to sell to the market that couldn't quite bring themselves to use a proper check chain. Now this was coming from a man that had used check chains 'properly' (not my thing) during his career with the Met. He said that someone invented the half check to be the 'soft' option to the normal check chain and it was a complete waste of time and a 'bad' thing as a normal check chain used 'properly' is designed to press on a dogs nerves behind their ears (not strangle them).. the half check can't do that so just yanks dogs necks around.
That's funny. Honestly, I wouldn't trust anything regarding training dogs from a K9 police unit. The best police dogs aren't trained by the police, they are bought already trained by protection dog sport trainers. Pluto, the worst police dog in the world, was probably trained by a police dog trainer.
I always thought that half checks were essentially martingale collars, which were invented for breeds with smaller heads so that they wouldn't back out of them. I'm sure, however, that it was marketed to the public as a more humane version of the check chain since there is a limit to how tight it can get around a dog's neck.
The reason check chains are positioned high up on the neck and behind the ears is so that it doesn't block a dog's airway when tightened and also so that it can compress the brachial nerve, but honestly, how different is that compared to the Halti head collar that presses on the sensitive facial nerves? You're never supposed to yank a dog's neck around with either the check or half check.