I read with some amusement TB11 contribution. I find it hard to believe that people out of the USA are rogues whilst those that are within are angels! I am sure that not all the people on that side of the pond are a cut above the rest otherwise there would not have been ENRON and the rest.
Needless to say when it comes to information processing one does need to take reasonable care. There is no way that one could have access to another person's account because that would tantamount to fraud and Banks would be liable, unless one would not have taken reasonable care (the accent is on "reasonable care") and facilitated fraud. Definition of what is reasonable care is very wide and case law gave different interpretation.
Trade can never be made unless there is reciprocal faith between the seller and buyer. Sending money in advance can benefit the seller but not the buyer (hence payment in advance by means of SWIFT transfers only benefit the seller and not the buyer). With documentary credits it will benefit both but are expensive and still not full proof since Banks only deal in documents and not in goods. Consequently, the basis of any trade has to be faith that the transaction would go through. If one does not believe that than one would be advised not to indulge in any trade at all.

Reuben