I'm not really sure what you are asking. Are you asking if modern riot tactics can be traced back to the idea of a body of infantry moving as a tight group? Or are you asking if modern riot tactics are deliberately modeled after Roman formations, as in someone sat down and said "let's emulate Roman heavy infantry on purpose"?

The vague and broad idea of infantry with shields fighting as a group is hardly revolutionary and clearly predates the Romans. I know a have a book at home dealing with modern law enforcement the and crowd control that focuses on major riots and civil disturbances over the last fifty years or so, I'll see if I can find anything there about the origins of specific tactics used by riot police and see if there's any clear indicator people tried to emulate the Romans.