My SO helped with the crowdsourced civilian effort to dispatch water rescues of stranded people. The effort is wound down now; it will likely be hailed as a coup of "social media", but that's overhyping the social media aspect. Social media got the word out of where to go online to enter the coordination, but had little to do with the actual coordination itself. The group my SO worked with coordinated mostly through…
My biggest concern related to this watching twitter during the initial period was not so much 'fake rescuers' as people with good intentions going bad.
e.g. those that setup a website/twitter handle/phone number soliciting rescue requests either not handling information correctly, not being able to handle the volume influx, going dark while sleeping or days later, etc. But then people assuming that their requests to that service were being handled - the flip side of that is people making requests to multiple services potentially overwhelming not just actual rescuers but even just the information collection services themselves.