Per US DOJ any PII over the air by any LEA must be encrypted. So yes, there is an mandate. Its been stated as the force behind full encryption for at least one county here in IN, and is why several other States are now rolling the big E out. Personally Identifiable Information, or PII such as SSN, etc. The only place I know of that still is even using this over the air is Mississippi, though. Most Information Databases in use by LEA's no longer allow the SSN to be used as identification information. Though any lawyer could quickly argue that DL/OL/ID being read over the air is PII. (Though the main reason behind the security of PII is identity theft and to "protect suspects privacy") There are some places that solve this issue by simply taking all that information to secure TG/Ch, or using MDT/Laptops/Cell Phones, and thus no need to go E on dispatch. Then again, just stating an subject/suspect name over the air is assuredly PII. But such is life now.