I’ve made a replacement bracket that is slotted, it lifts up and pivots to allow towers to be removed while keeping the bracket attached. I’ve used long button head cap screws and put a locknut on the back to discourage removal 
Brilliant! Mine went missing over the last two years while loaning out the field. This probably would have saved them. I would put loctite the fixed nut or maybe two nuts to further discourage removal.
Let me know when you start selling them. Great idea!