A pretty dramatic thought; perfection or disaster. Let's talk about avoiding disastrous lighting problems. Doing so definitely helps your ROI and assures a "wow".
We're not going to talk about Par Cans, Fresnels, etc. As an event or meeting planner or manager, the important thing in this case is good communication with your production team.
Bring your producer and technical director into your first team meetings. Lighting, sound, video and staging should follow once you have the vision of your event.
Things that sound so simple, but done on the fly due to poor communication can be costly. Things that sound so simple, and done without communicating in advance to your producer can either not happen as you envision or not happen at all
Some examples of "simple" that could be a disaster, but can be avoided with good communication:
1- Planner wants stage set for 4 person panel with all panelists center stage on high stools and moderator at a lectern, stage right. During chats with another planner, the decision is for the panelists to be seated on two couches on a diagonal. They will omit the lectern and have moderator seated on a chair. The lighting designer and your producer haven't been told of this change. Of course, the different seating needs to be sourced quickly and the lighting designer has to re-focus his lighting. Much stress and potential errors could occur.
2- The planner has a banner made that is hung on the back drape of the stage. In a meeting prioor to the event the producer asks about the fabric so he can be sure that it is lighted correctly. Planner "thinks" that it's a fabric banner, but the banner arrives and is shiny vinyl. Lighting, once again has to be re-focused to avoid glare.
3- Your producer asks that the teleprompter arrive early to set up, but our planner does not wish to pay for the extra hours required. Disaster is ahead as the teleprompter operator sets up the glass only to discover that the lighting that was set earlier now causes glare on the telepromter glass. It actually may be too late to re-focus lighting at this point and a difficult situation occurs. Two things that could happen are that there could be a reflection off the glass that becomes a distracting glare on the set or the speaker can't read the teleprompter because of the glare caused by the lighting.
I could go on an on with this, but as you can see, good communication with your producer and production team is essential for that perfection. Sometimes management and/or procurement feel that contracting production early in the planning stages can cost more money. However, if the objective is a successful event and ROI, then doing so would probably ensure both. The Producer and Technical Director as part of your team can usually suggest alternatives in production that could save dollars for you and create a better production and thus a better experience for your audience and help ensure that you do get ROI.