[pjg]

If I use your reasoning then Americans should be as afraid to write paper checks since each check has the owner account number on it, hence anybody who gets a paper check can syphon money using ACH. Not really! (Paper checks - even today - move more money than Credit/Debit cards)

ACH is far more complex then being able to withdraw money from someone's bank account with just their account number. To be able to initiate an ACH transaction bank level authentication is needed and it can only be done from an authorized bank. Can you give me a use case where someone can withdraw money from my bank account using just my bank account number ?

Any ideas ?

There is no logical reason for someone not to give out their bank account number anymore than their Credit/Debit card number. In both cases consumers are indemnified by federal regulations. However perception is bigger than reality - just like in the early days of the Internet/e-commerce people were afraid of using their credit card numbers online so are they wary of using their bank account numbers online.