I don't really see this as an issue if your business is setup correctly...
No single person should have control over money, that's pretty much standard process. For example large businesses who need to pay big invoices, payroll, etc. will require multiple authorisations before a payment is processed.
Same principle if a sales guy is accepting payments - it shouldn't happen! They handle the sales, your office/AP handles the money.
It's something every business should absolutely be aware of, and as your business grows you need to continually keep track of the access level available to staff, and make sure there's a degree of separation. Basically it's not a software issue, it's an organisational structure and process issue.
Having said that, yes an audit log would be nice.
