Radio signals do not penetrate through stone or concrete well which causes increased battery drain. You also have the issue of perhaps diminishing oxygen and co

Radio signals do not penetrate through stone or concrete well which causes increased battery drain. You also have the issue of perhaps diminishing oxygen and cognitive impairment caused by shock and crush trauma. It would be better for battery life for people to just text a friend or family member and say "crushed under tons of stone at home, please send help". Nobody is going to do an AMA on Twitter while buried using up the precious battery life for retweets and likes.