I have been in too many groups that have been told what to do, instead of each person getting what they are best at. This is the same when I work with event planners. No one that is in the group for the event gets picked for what they are good at, instead it’s what convenient for the boss.
I understand wanting your employees to get more experience so they are good at everything, but there is a time, place and way to do this so that your event doesn’t suffer in the meantime. If a person wants to get to know a different area of the event planning process, he/she should partner up with someone who has done that area of work before. After learning and understanding it the employee can start to venture out on his/her own with supervision. Once this employee feels comfortable, and they are performing up to the companies standards, then they should be allowed to work on their own.
If things go wrong due to the fact that a boss just gave projects to different people without knowing their skill sets, the event could wind up not running smoothly. If this is the case that company could lose out on a lot of future events. If the time is taken in the beginning to figure out what each individual is good at, the less headache will help happen down the road in the arguments that may arise.
Pick the person most qualified, train the ones to get them qualified and have a successful event!