The Madrid train bombing footage release is not a signal to any cells.
The footage was not released by any terror group.
There are official hearings taking place on the bombing and authorities recently identified one of the key terrorists responsible. The footage release no doubt ties into these events instead.
DLN....regarding the release of the train bombing tapes...like you indicated this coincides the the trial....but they have been shown so much over the last two days; it has made me wonder if somehow they are being shown to make people more aware of their surroundings etc.