There's a whole lot of stupid when it comes to encryption, within government circles.
First, "AES" encryption, is not encryption. It's the name of a standard, of which includes an algorithm (Rijndael), created by two Belgian cryptographers, Vincent Rijmen and Joan Daemen. The Rijnael algorithm is open and available to anyone who wants to use it.
In 2001, the American National Institute of Standards and Technology (NIST) selected Rijndael as the Advanced Encryption Standard (AES). In other words, AES is not the property of the American government, even though they claim "It's secretive American encryption".
On top of this nonsense, the NIST stated in the AES standard (FIPS 197) the technology may be used by anyone.
http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.197.pdf Page 1:
So whenever we hear total nonsense and lies from Motorola about AES being "heavily restricted" or "top secret" or "law enforcement or government only", it's all crap. Not sure who started these myths, but it has to stop. And the US Government has to start paying attention to what's stated in FIPS-197 PAGE 1, instead of making up their own "policies" (which are not law) as they go along.
The rest of the world also needs to start understanding the algorithm outlined in the AES is open for anyone to use. The source code is on the Internet. If they don't like it, too bad. AES exists in nearly every wireless gadget available to consumers, from smartphones, routers, TVs, intelligent watches, embedded devices, etc.
Any government or corporation which claims AES is "highly restricted" is misinformed and has a hidden agenda. In Motorola's case, it's to sell the APX radios instead of TRBO radios, for customers who want to use the algorithm outlined in AES. In North America, the APX radios sell for 4-10x more money than TRBO radios.
Hope these facts shed some light on why TRBO radios have weak encryption, compared to APX radios. It's all about profits and nothing to do with "restrictions".