Regarding my comment on correction levels, I wrote that in response to you saying that you didn't like most of the methods used to train police dogs and would never use them with your own dogs. I use the same training method as a gentleman I know who trains personal protection dogs - teach with positive reinforcement, proof behaviors with corrections. We follow the same basic principle of balance and fairness, of being as gentle as possible, but as firm as necessary; but the firmness of the corrections he is sometimes required to give to his dogs would be outright cruelty if used on my own.
If bred true to type, GSDs and Malinois are hard dogs and Cocker Spaniels are soft dogs. What may be required to correct a hard dog would make a soft dog exhibit avoidance behavior and completely shut down. Normally a firm word from me is a good enough correction for my spaniel. A firm word would not work on a working type GSD that is operating in fight drive mode (fight drive meaning the dog knows it can take down a grown man and it wants to do so/he loves the fight and knows that he can win it), firmly latched onto a bite work helper, and won't out when told by his handler. When you have a high drive hard dog, higher levels of compulsion are sometimes required to correct and control a dog.
My personal experience (not just thoughts, vague opinions on the whole thing) with police methods and the reason for my comment about not using police methods on my dogs, is based on a number of techniques that were discussed with me to resolve issues with my rescue Weimaraner - not my cocker.
She's not a GSD of course, but Weimaraners are a dog that have been trialed (unsuccessfully) as an alternative to GSD police dogs in this country (I don't know about the states) because of some similar attributes they have. She is a big strong 32 Kilo dog with a very very strong prey drive which on the odd occasion early on was directed at people (strangers that made her uncomfortable) as well as other dogs - although she's never bitten and never been taught to bite obviously. As a Weimeraner from working stock, she also has a very strong hunt drive. Her natural state when out and about tends to be hyper alert and very pumped up, she also has had serious fear aggression issues too.
The methods discussed with me by the police trainer to work on her, involved an element of shouting and dominating her (which my dog will take, but it certainly doesn't get the best out of her) and addressing two of the main problems that I needed help with (prey lunging and fear aggression) with choke chain correction. As discussed earlier, she was in a half check when I rehomed her and this is when I was told about half checks and it was suggested she be put into a full check chain. With one technique discussed, the check chain was to be attached to a long line and when the dog reacted she would be checked and possibly bought down with it.... that was when I walked away. I agree very much that different dogs need to be handled in different ways, and when I really need my Weims attention if she's not on a lead, even now, I will shout and use an 'I mean business' voice - I have to, to snap her out of the very focused state she gets into at times (she will actively 'stalk' and lunge if not stopped).
I questioned what you'd said because partly, you were very vague in your post and also because I've resolved the issues with my dog (to the best they'll be given her start in life), without the 'hard' handling
I was offered by the police dog trainer from the Met (Metropolitan Force - which is our London police force). Which surely for a family dog, is without doubt the best way, rather than the type of police handling/training I've been exposed to? I've managed her by instilling different behaviours and reactions to certain situations with distraction and reward based training - it is now an ingrained behaviour and one I'm very proud of achieving with her through a lot of hard work. From what I saw of her early on, some of the 'hard handling' and aversive techniques used by police trainers here did sometimes stop her in her tracks, but didn't work if you weren't attached to her at the time, it didn't change her behaviour for the better long term and only heightened her tendency to be pumped up and stressed. None of this would have given me the reliable dog I needed.
All this came up because of my comment on half check collars which was as I said, from this particular police dog trainer which you suggested probably wasn't from anyone that had any real experience of training police dogs... You've been talking about training in the states and generalising about my comments based on your experience and a police handling unit in a different country that appears to be very different to my experiences. So I stand by everything I've said - including the information I added to this post on half check collars as a training tool.