I have been involved in implementing MI with officers for about 5 years now, based on my experience and discussions with others I feel very strongly that several pieces need to be in place in order to ensure effective implementation of MI. First and foremost, officers must have the philosopy that it is part of their job to facilitate change in offenders - if they believe that their job is only to monitor, enforce conditions, and/or refer to others for treatment than MI is not for them. Also, a 2, 3, or 4 day workshop in and of itself will not result in officers learning and using MI correctly. In fact, there is a fair amount of research indicating that MI skills cannot be learned/sustained unless there is substantial coaching/supervision/followup (I'd be happy to send the article if you'd like). Finally, I strongly recommend using a MI trainer who knows/understands probation - people who have only trained MI in substance abuse will likely not be as effective in training officers as those who have trained officers (there are several out there).
We are in the midst of implementing a training protocol that includes a 2 day initial training, audio/videotaping of officers' interactions and rating of such to ensure MI adherence, monthly coaching/feedback, 1/2 day to full day "booster sessions" 6 and 12 months out, and training of supervisors on how to coach/supervise MI in officers. Unless you are willing to commit to a level of training such as this, you will likely not end up with officers understanding/using MI and will have wasted precious training dollars.
Feel free to contact me if I can be of further assistance. Melissa