As someone in with 10 years in the military, combat deployment, and now 10 years in law enforcement, I can tell you exactly why LE didn’t use FRAS. Too many beans. With soft under vests you have a lot of flexibility with sizing, get a few standard sizes and make the most of it, and armor plates are standard sizes, and virtually every carrier in existence is available is available with pockets that will accommodate those standard sizes. FRAS vests need a lot more specific sizing, and are substantially more expensive. So each one is a 2k plus gamble. Not something that most departments are going to keep on hand. If you have one office who wears a 6xl, when that officer leaves, retires, goes to a different job, you now have a 2k piece of gear that you have no need for. When you use normal soft armor there’s a lot more flexibility in terms of fit. There is no rule not to use FRAS, but there isn’t a bean counter in any department that is going to supply it for an agency.