Regarding policemen as being people in the front line on a daily basis may I say that I have trained with one for many years and taught one. Both report that Aikido itself has never let them down and both have over twenty years experience in all kinds of situations.
I agree, it has at times been messy, but it has never let me down either.
Although there is something to be said regarding 'it's the fighter, rather than the art' that matters. Some dan grade aikidokas I have trained with couldn't fight their way out of a paper bag, whereas some people have natural talent without any sort of formal training.