The lines in the sidewalk have never caused any harm that I know of, except when I used to roller skate as a kid. But an irrational fear of radiation is difficult to combat through education. Two reasons for this are that radiation concerns are derived from primarily political motives and from health concerns. Thus people's aversion to radiation derives from an inexorable link to nuclear weaponry and a potential for causing cancer. The connections that exist are irrefutable.
Atomic bombs involve plutonium and tritium, radioactive isotopes.
Being against nuclear war and cancer has merit. But radiation is natural and all around us. In sunlight we are constantly exposed to radiation. Objects as common as bricks and bananas emit radiation. Low-level radiation can cause genetic mutations, but so can any of hundreds of chemicals we eat or are exposed to daily.