According to an Associate Press article, it's quite common for employees to snoop through customers' personal data.

Vast computer databases give curious employees the ability to look up sensitive information on people with the click of a mouse. The WE Energies database includes credit and banking information, payment histories, Social Security numbers, addresses, phone numbers, and energy usage. In some cases, it even includes income and medical information.

Experts say some companies do little to stop such abuses even though they could lead to identity theft, stalking and other privacy invasions. And companies that uncover violations can keep them quiet because in many cases it is not illegal to snoop, only to use the data for crimes.

But of course, if they didn't store all that unecessary data, this would be far less of an issue.

(H/T to The Consumerist for the link)