Who, if anyone, realised Harry and Cedric had left the maze?

This question occurred to me when I was re-reading Chapter Thirteen of OOTP, when Hermione says 'Look, you don't understand what it was like after it happened, you arrived back in the middle of the lawn clutching Cedric's dead body ... none of us saw what happened in the maze ...we just had Dumbledore's word for it that You-Know-Who had come back and killed Cedric and fought you.'

Personally, it seems somewhat implausible that no-one noticed they were no longer in the maze, particularly when Harry and Cedric must have been in the graveyard in Little Hangleton for a considerable amount of time (an hour at the minimum, by my logic). Yet there seems to be little evidence to support anyone having noticed they'd gone.

It's also plausible that it was assumed they were simply taking their time getting through the maze, and no-one was worried by this. Also, with Moody/Barty Crouch Jr patrolling he could have simply lied and said to anyone concerned that he could see them with his magical eye, so there was nothing to worry about.

Would Dumbledore have realised something was amiss? Would anyone?

Particularly, if the teachers had realised something had gone wrong, would the students watching have been informed? Personally I highly doubt they would have been, for fear of panic, but I think they might have noticed perhaps a dark atmosphere.

I'd love your opinions! This is driving me mad

Fenella x