The U.S. Coast Guard sent 45 people back to Cuba on Sunday after stopping them off the Florida Keys last week. They were found in four boats on Wednesday and Friday as U.S. authorities report the largest exodus of Cuban balserossince 2016. At 11:30 p.m. Wednesday, a civilian reported to authorities a rustic vessel sighting 12 miles south of Boot Key. On Friday, civilians reported three additional rustic boats to authorities in a 15-minute span. At 11:45 a.m., the first one was found 17 miles south of Long Key. And at noon, two were spotted 17 and 22 miles respectively south of Big Pine Key. On…