Where do you 'stop'?
Its not in regs, the same way tie pins of the 80/90's weren't, either. Officers have chosen to wear medal bars on body armour, thats not in regs either, its one up-manship.
We are a Police Force/service, supposed to be disciplined. If the issue is remembering our fallen, then donating to a fund would probably yield more money for that cause than the price of a badge!