There are a couple of minor settings that also give you control of the event once registrations are present.
Privacy
This setting is dependent upon teams being created and players assigned to them. It controls whether a parent or player who is not a Team Official can see the contact details of other players and parents.
Generally, setting this to Yes probably won't accomplish much (in our opinion). Your teams may bypass it by having the Coach or Manager (who can always access everyone's details) distributing contact lists off-line.
The reality is that for making things like intra-team carpooling easier, this setting is best left as No.
Limits
The grading process can sometimes mean that you're swapping players between teams fairly regularly until it all settles down. Activating the first setting means that if you assign a player to a team, the system will automatically pull them out of any other team that they're on.
You can also set a limit on the number of players that can register for an event. Remember that each registration can have one or more players present, and it is the actual player total that is meaningful, not the number of registrations.