Why does AdSense need to "challenge" my bank account?

[Mikl]

If you think a challenge deposit is intrusive, what do you think about the demand for direct debit access to the account?

I don't find it intrusive. I just don't understand the reason for it.

I don't have a problem with direct debit, mainly because the banks impose very stringent regulations on it, and guarantee the customer against any loss.

Mike