Who gets the Imperius curse? And when?

[paul_terzis]

No: HPFGUIDX 103857

I feel that indeed there is something significant in the scene where 
fake Moody put under the Imperius curse the whole class in GOF. We 
all are considering the future events. But why not someone is still 
under the imperius curse the whole time of GOF and OOTP? And to make 
it even more striking, why not be more than one under the imperius 
curse all this time? Just imagine the possibilities. Fake Moody 
under the cover that he shows them the curses, he could enlist to 
his master's bidding any student of Hogwarts!!! What a predicament! 

Paul