Spectator's Mode, Fog of War feature

Solution 1:

There's a 3 minute delay in spectator mode, so the only cheats that people have cautioned about so far would be watching a ward get dropped.

Since a ward is alive for 3 minutes long, a spectator could communicate that to someone on a team, and the team would instantly know that the ward there was now gone.

Solution 2:

Since keeping track of the enemy team's warding is nigh impossible (you have to be looking RIGHT at the spot it goes down in order to pass along the information in a timely manner. Summoner's Rift is a large map and warding is not a one-person job.) the only real advantage that a spectator could give to a team would be the times that Red/Blue buff, Dragon, and Baron respawn.