Data Loss Prevention solutions are the only class of security products I can think of that attacks the problem in a worst way than antivirus do... That's say a lot.

All the time spent implementing those "solutions" would be better spent deploying proper access control, so that retards that may inadvertently upload confidential data to box don't have access to the information in the first place. As a bonus, it also protects you better from malice and not only stupidity.