I have a friend whose apartment was broken into at night while he was sleeping by the police with guns drawn to do a "wellness check" because the mother of a friend of his called 911 and reported him as possibly suicidal. Later they charged him because he grabbed a gun when he heard what he thought were intruders in his house.
What is the legality of such entries?
Obviously, if anonymous 911 calls are acted on, then a "wellness check" could provide the police a pretext to break into anybody's house, since the police can simply have an informant under their control call in an "anonymous" report on someone to generate a "wellness check".