Safe enough, I think. Any problem's are at the bank's expense, and they do enough to keep the level of problems down without locking the system down so tightly that it's too inconvenient to use.
Contrast with the ID Card programme, where the government doesn't give a stuff about our convenience, requiring interviews and fingerprinting and fines etc, but is quite happy to share the information across government for its own convenience!
And you all know, security / Is mortals' chiefest enemy. (Macbeth)