Which factor can cause a safety net to become defective?

A safety net is designed to provide a vital protective measure against falls, particularly in scaffolding and construction environments. The factor that can cause a safety net to become defective is the behavior of individuals interacting with the net. When people jump on the net, they exert a force that can lead to damage, tears, or structural failure of the netting material. This impact can compromise the integrity of the net, potentially rendering it ineffective at absorbing falls or impacts.

In contrast, proper handling and use of a net by trained personnel and conducting regular inspections are crucial practices that maintain and enhance the net's effectiveness. Weather changes can affect materials over time, but they do not directly cause immediate defects like jumping can. Therefore, ensuring that safety nets are not misused is essential for maintaining their condition and ensuring safety on work sites.