I think they could be useful if the law enforcement departments carefully consider the context of where and when.

Of course, the user would be sure to have the needed training and experience -- you will not immediately use them well, especially under adrenaline-pumping situations like an officer could be in. See this link to someone falling off a T3 Motion, probably being overconfident of how easy it is to drive them: http://www.youtube.com/watch?v=wjldrPLX7Pg