Telephones are not encrypted because back in the late 1800s, when telephone systems were being developed, any sort of encryption was far beyond the capability of the hardware, even if it had been something that people would have thought important.  Since then, compatibility with existing hardware has been considered more valuable than protection against eavesdropping -- listening in on a PSTN conversation requires physical access to the wires involved, and is difficult for anybody other than the phone company to do. 

That said, there are encryption-like devices for telephones known as scramblers, originally developed around the time of World War II.  Modern scramblers are every bit as good as other encryption systems.

Why are PSTN lines not encrypted?
So I've been watching a lot of the 2003 TMNT cartoon, and I've noticed that whilst they claim to be ninjas they only seem to use their own iconic weapons.

Is there any evidence that they train with other weapons? I'm not asking about just use, I mean proper training, involving kata or some such?

Because I like to pretend all the reboots and remakes share a sort of pseudo-canon I'm happy for answers from the comics or other cartoons.
