He filed about 2 weeks after opening these accounts.
It is sort of like "Which came first, the chicken or the egg?" If the sole purpose of the accounts was to facilitate a fraud on the trustee, then that's when the first act occurred. Yet, the fraud was not consumated until he signed the petition omitting them as assets.
However, the bank would not be chargeable with any knowledge of the petition's omissions; i.e. the clock would not begin to run on SAR filing until the bank received the trustee's order to freeze the accounts. Even then, I would not say that every bank receiving an order to freeze accounts would automatically be on notice of the fraud. This one was somehow able to connect the dots.
P.S. What a great father, involving his teen aged son in the fraud.