Final answer:
'No Smoking' signs are typically required in smoke-free areas to communicate smoking prohibitions and protect public health, making the statement mostly true.
Step-by-step explanation:
The statement "'No Smoking' signs must be posted at all smoke free areas" is generally true. Rules regarding smoking in public places have been established around the world to protect public health. These regulations often require the posting of 'No Smoking' signs in designated smoke-free environments to clearly communicate the prohibition of smoking to individuals. This is crucial as exposure to secondhand smoke can cause serious health issues in non-smokers. Therefore, effective communication through signage is necessary to enforce these regulations and ensure that non-smokers are protected from the dangers of secondhand smoke.