I had an idea about a slightly different type of protest that could be effective but at the very least would get attention. Fans of clubs in Sweden have done it.
It does require everyone getting on board, but basically what the swede's did, was stay absolutely silent for the first 10 minutes of the match. 10 minutes is a bloody long time to stand silent for, but it'd have a really weird effect. While it may make the players uncomfortable, think of the reaction when the 10 minutes is up and everyone gets out all the frustration. Mind you - it'd be interesting to see what happens if we score! we'd have to be disciplined.
The other idea was similar, but instead of staying silent (as i say, this would be most effective if everyone does it) when the teams kick off, everyone turns their backs on the pitch for 5 minutes or something. Considering it'll most likely be patches of people who won't take part in any protest, this might work better. Block 15 and alot of the CET stand with their backs to the pitch for 5 mins would look good.
Either way, it would need to be organised and the message would need to be sent out to as many fans as possible.