I dont understand

Well, in the book ((I think - I haven't read it for about a year!))

Spoiler:
Snape tells the Minister that Sirius had put a Cunfuddlement ((or something)) Charm on Harry Ron and Hermione. The Minister then believes that Sirius made Harry attack Snape, not that Harry did it of his own volition

Originally posted by shaber
Did the Ministry let them suck out souls when they wished it? I inferred that they were only allowed to do that occasionally. I was wondering why the Dementors have to serve anyone at all. Voldemort can offer them far more scope for their pleasures than the Ministry because he is unscrupulous, but the Ministry must have had some way of preventing them from doing just as they liked.

Dementors were only aloud to suck souls when the ministry said so. The rest of the time they could only make you relive your worst memorys.

and i agree with shaber why would the all evil dementors that could reduce you soulless with one kiss do as they were told
why didnt they roam free kiss as they wanted ? why do they have to follow someone?
they a capable of killing all on there own so the ministry must have had something to make them do as they were told and now voldy has the power to do that ??
wonder wot it is???