Every few years the UK arrests some phone-phreakers pour décourager les autres. My favorite was the guy from my University, who had a coin to use in phone boxes, attached to a piece of thread ... :-)
But seriously, it is actually way more difficult to generate control codes from an end-user (terminal) phone than the article makes it sound. As an ex long-distance telephone exchange manager, I can tell you that the exchange equipment (at least in the UK) would detect this and disconnect you if you tried. However, if you had a key to one of the long-distance repeater boxes ...

I still have the last printed issue of 2600 magazine.

This reminds me of the movie Hackers, where they use payphones and devices that emitted certain tones to hack into stuff.