rjcombo confirmed the upcoming Spectator mode will be on a delay to insure no one "Ghosts" games ( assisting a team via the spectator seat by revealing enemy locations or what not ).
[ initial ]
Spectator will be available for custom games only at launch, which will improve shoutcasting for tournament events not organized by Riot. We have, however, been building the feature with an expanded scope in mind. There's some pretty exciting stuff on the horizon for spectator.[ Response to delay questions ]
As for cheating, there will be a delay for spectators to prevent ghosting.
While the delay time is still subject to change, the current intention is 3 minutes (the duration of a ward). We don't believe there is enough of a ghosting advantage beyond that time to really affect the outcome of a game. High skill players are quite capable of tracking neutral camps on their own.
- rjcombo, Senior Game Designer, via the official forums.