A "passive bystander" is someone who sees something happening but does not get involved or help in any way. They just watch without taking any action. Full definition
Microbes are not just passive bystanders in a given environment but are essential to many life processes. (kavlifoundation.org)
Gen Z wants to be part of the process of learning, not passive bystanders. (elearningindustry.com)
«By teaching D&T, we are ensuring that all children are not just passive bystanders in our increasingly technology - driven world, but are informed citizens who understand how design impacts on their quality of life and how technology can be used for the benefit of mankind.» (educationbusinessuk.net)