During the Majin Boo Saga, in Dragon Ball Z, the Dragon Team thinks that Gohan is dead, even after they revived all the "good" people that have died that day.
If Gohan was really dead, he would have been revived, like Kibito was.
In episode 243 of Dragon Ball Z (episode 125 of Dragon Ball Kai), Videl and Kuririn share a few lines more or less like this:
VIDEL: Hey, hey, hey! Everyone has already decided they're dead, even though we haven't even found any bodies! How come!? It's strange that you should know that Gohan-kun has died!
KURIRIN: Look, we know how you feel, but seeing as how we feel absolutely no Ki from him It must be that Gohan is no longer of this world anymore...
VIDEL: I don't believe it I won't believe it! I absolutely won't believe such a thing! Gohan-kun...
Don't they remember that they just revived everybody?