How would bitcoins for businesses work?

[chayskie04]

How would you use bitcoins for a business if someone who has access to the company's wallet is able to just take it and drain it without anyone knowing?

Say Walmart starts accepting bitcoins, they pay for new stores with bitcoins, pay vendors, pay for merchandise, etc.

Their accountants are writing checks, keeping track of purchases etc.

If one of the accountants decides to just write himself a check for a buttload, there is a paper trail and the person is prosecuted.

If Walmart is using bitcoins, the accountant takes the bitcoin wallet, makes a copy, takes it to the nearest library and uses it to send to hundreds of new bitcoin addresses of his own, and he is rich.

How is this prevented?