The laws protecting the helper definitely help as well. As long as I'm not tremendously reckless or meanspirited I cannot be blamed (sued) for any damage I do in the course of providing first response aid. In fact I can be sued for not trying (calling for help is sufficient).
The US has so-called "Good Samaritan" laws as well. Some of them go so far as to protect untrained individuals who injure or kill someone while attempting to render aid.
