I've just watched the movie 'In Time' for the first... umm... time.
One thing that surprised me was how easy it was for other people to steal someone's time. It merely took a handshake and some mental will to drain someone else's time – whether they're awake or asleep, co-operating or not.
Why wouldn't the system have included a safeguard to stop people stealing time so easily? Or, even if the basic system didn't have that safeguard, why wouldn't someone have invented such a safeguard?
It's noteworthy that the rich girl character carries "only" a decade with her, and has to be surrounded by bodyguards at all time. But, time isn't like money, where, if someone steals what you're carrying with you, you can just go to the bank and withdraw some more. If someone steals the time you're carrying with you (whether it's a year or a millennium), you're dead and can't go to the timebank to top up! In that context, why wouldn't someone invent a safeguard and sell it to people who wanted to protect their time from theft?