Best idea I can think of is to use Darwin Adverse Selection to remove and/or prevent repeat offenders until the gene pool has been locally cleansed. My wife, for example, has a nine millimeter "solution" she has been trained to use, but she is also savvy enough to realize there are some situations she should avoid at all cost. No loud whistles for her, although those do have some effectiveness if immediately used. I believe that punishment does not deter crime, unless it is "life behind bars with no chance of parole" which we don't always seem to believe in here in America. Maybe that works to get the worst of the worse off the streets, but it does nothing to deter future criminal activity. Sorry to bring the sad news, but some problems do not have a solution.
