Well, I guess we can only look at how this kind of information has been disseminated before. There has been several discoveries in the past of large objects that would have a non-zero possibility of hitting Earth, and some of those objects were large enough to cause catastrophe had they hit. So far information on these objects has been released early, with later followups (after tracking the objects for longer, or after finding the same objects in older photos). Fortunately the followups have all concluded that the probability of a hit was low.