When the admin creates a new game round, they provide the timestamp when the round starts. The only validation done specifically on the start time is that it must not be in the past.

Since there are no limits to when the round can start, if an admin mistakenly provides an invalid value and starts it too far into the future, any and all operations are blocked until the round is started.

Add a maximum allowed start time deviation from the present. A suggested value is of 7 days. High game usage will probably never allow it to start at such a difference from the last round but if needed more time, starting a round in a month from now for example can be achieved by simply calling the createNewRound one week before the estimate start time.