Hello,
I tend to agree with you as well. It sounds paranoid that SB firms are after you if you trade large size, and it's too easy to find alternatives to be so. Besides, large size for SB, say >£500/pt, means that you have at the very least a £100,000 minimum bankroll, in which case you are: A. a professional trader who has grown his account over time and will know immediately if the SB firm is trying to hustle him before it becomes a problem; B. wealthy but just using SB for punting, which is fair enough but means you likely have a limited understanding of financial trading and will lose money because of your own errors, not the SB's.
On a side note though I have found the Gann excerpt quite counterintuitive.
To understand human nature and exploit human cognitive weaknesses for successful trading is indeed paramount as far as I'm concerned, but I disagree with the "buy/sell the bottom/top against the public" bit.. Whether the public is right, wrong, knowledgeable or not, is not relevant if it represents the majority of volume. I have found that it can be most profitable to understand human weakness and go along, rather than go against.
But that's just a small comment, perhaps I misunderstood the original idea.
