Exactly. A Cold War spy listening in to conversations in bugged offices was stealing information just as much as anyone who's siphoning off data from a database. Monitoring in the latter case isn't easy, any more than finding all the bugs in all the offices in the Cold War was easy, but as someone involved in minimising security threats, you do your best. Doing nothing because it's difficult is just not an option.

@Brian, I hold by my original statement. This isn't a technological problem; it's only the solution's implementation that's technologically based. What you're trying to achieve is as old as the hills, and it's only the tools used that have changed.