See I dont agree - sorry hunkashlie said:For example, at the Quidditch Cup, safely storing active portkeys would be impossible, as would even knowing when they would be needed for the return trip. The portkey that took them to the hospital, again, was only one way because the return trip wasn't needed.
You need to look at it again - they knew when the World Cup would end - and yes they could have stored the portkey's fine - in fact it would have made more sense than trying to 'charm' more objects for the return journey's.
Same with the hospital trip - i think there is every reason to assume that if it could be made a 2 way affair - it would have been.
This is all strong evidence that they are one way deals - and this is fundemental in the question to this thread - it would mean that someone would have had to perfom portus - as such who was it.
I know we can all too and fro over the portkey thing till the sun goes down - but you have to remember it is a fundemetal part of the question of how the spirits knew and how was it changed ...