Role-playing can be an excellent way to demonstrate a desired behavior or action. Seeing a new method in practice can be much more memorable and clear than just having it described.
Role-playing at an event, onstage, however, can be tricky:
When done poorly it can be dull, ineffective, and painful to watch.
When done well it can be a refreshing alternative to straightforward presentation; the dialog and multiple-person format keeps people engaged more than a single speaker, and seeing the situation in practice (and even getting to participate, sometimes) is highly valuable.
Here are some tips for avoiding the role play roulette and having a successful on-stage role play at an event.
Do: Set it up properly
Context is crucial--the audience needs to know what the scenario is, what it's supposed to be teaching them, and how they can apply it.
Don't: Assume you have actors
Not everyone is good at playing a role. Pick people who are good on stage, even if the role-play isn't in their normal "role".
Do: Help your actors along
Consider a "radio play" or other format that allows performers to have access to a script. A combination of rehearsal and the crutch of the script allows the presenters to sound less "memorized" and more dynamic.
Don't: Make role play a one-way experience
Let people in the audience practice at their tables, with their peers, in addition to performing on stage. If your presenters have the skills, allow the audience to throw out suggestions for the presenters to improvise.
Do: Keep it short and varied
Add in scene breaks (with, perhaps, a review game or question session or verbal review). Accept that you aren't going to get to cover every single scenario and key piece of dialog (without going on ad nauseum) and keep it very high-level.
Don't: Be afraid to be silly
Even if your situation is very serious, the role play on stage doesn't have to be. Humor is appreciated and necessary. Looking a bit silly for the greater good is a gift the presenters can give to their peers.
Do: Keep it high-level and broad
Hyperbole is an effective way to illustrate situations. Will audience experiences be as broad as you play on stage? No, but getting the exact scenario can be overly-detailed and tedious (and may be too specific to apply to a majority of the audience.