>>>The amounts on those checks look normal to me, so I suspect that there is some kind of hidden security mechanism at work.
>
>Probably! My bank can tell immediately whether I endorsed the back or not when I use Mobile deposit, so I suspect there's a lot going on behind the scenes.
>
>FWIW, outside the US all our invoices go out electronically via xero.com and all payments are deposited electronically and correctly reconciled in Xero. I haven't received or written a business check in years.

What is xero.com? Who owns it?