Unique as far as I know, at least in a scientific collaboration like ours. But we were unusually sensitive to the risk of false detections given (a) skepticism

Unique as far as I know, at least in a scientific collaboration like ours. But we were unusually sensitive to the risk of false detections given (a) skepticism of LIGO's prospects from other physicists, and (b) the lingering stain of a false detection claim, from a bar detector, a few decades earlier. We believed that if we had announced a discovery that turned out to be wrong, it would probably have meant the end of our experiment, and in practice the end of the field, at least for a long time. It was fortuitous that the first detection turned out to be gold plated and unambiguous, otherwise we would have probably published a bunch of "we saw something interesting but can't claim it as a GW discovery" papers on the next few weaker events before we would have felt comfortable making a confident claim.