Being citizen of a high risk country or have businesses on risky countries AKA china, iran, mexico, venezuela...

Cash deposits on different branches in a short amount of time

Big deposits and movement of money in comparison of what your average balances are or according to the info you provided when you opened your account.

Sometimes they call you or Email you before to ask for info on the movement of money. But once the desicion is made, there is no turning back. However after 1 year you might be able to open a CC...