Yes, just take the old phone booth as a example...

People tell legandary stories of how they "hacked" telephone systems. {Coin operated} No matter what the companies did, there were someone who got past their protection mechanisms.

Then the companies dropped the {coin operated} systems, and switched to pre-loaded smart cards. Now people found ways to load or create these pre-loaded cards and they phoning for free.

I guess if it's there, it needs to be "cheated" or "exploited" by someone.