I know someone who ran into some trouble a while back. They weren't quite doing that volume of cash in and out of their account, but it wasn't too far off. They were using tellers exclusively, but they were visiting several branches. I suspect they flew under the radar for the most part, except that one particular teller found a reason to cause a problem. A note was logged on their profile and cash exchanges started to be denied for anything more than the most modest amounts. This person managed to get the situation cleared up, but now restricts their activities to a single branch where the staff knows them well and what they're doing (ie: searching for particular kinds of notes, etc).
My advice, to be taken with a grain of salt, would be to scale it back a fair bit. Assuming a short month of 20 business days, you're cycling through $1,000,000 at HSBC and $400,000 at both CIBC and Scotiabank. Those kind of numbers going through your account each month will surely raise some red flags sooner or later, particularly at HSBC. If you are on good terms with some of the tellers at your banks (eg: you're both on a first-name basis, not just another customer, etc), then maybe start chatting about what you're doing. Get to know the rest of the tellers at your branch(es). Get to know the manager who supervises the frontline area. Have a talk with them to clear your activities and make sure it's OK. If you can avoid having transactions run through your account (eg: straight cash exchange), that's better as it keeps the on-the-books cashflow down. Avoid busy times at the branch, and when you do visit, come prepared and make things easy for the tellers. Dress well, but I'm not talking business attire or anything... Just a level or two above classic "people of Walmart" calibre. I could go on, but I'll assume you get the idea.
Good luck.
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BWJM, F.O.N.A.
Life Member of CPMS, RCNA, ONA, ANA, IBNS, WCS.
President, IBNS Ontario Chapter.
Treasurer, Waterloo Coin Society.
Show Chair, Cambridge Coin Show.
Fellow of the Ontario Numismatic Association.