What triggers a high-risk inspection?

A high-risk inspection is triggered when the watercraft has been in a high-risk waterbody recently. This is because certain bodies of water are known to have a higher incidence of invasive aquatic species, which can harm ecosystems. By identifying watercraft that have visited these areas, inspectors can take the necessary steps to prevent the spread of invasive species to new waters.

High-risk waterbodies are typically identified based on previous infestations and the types of species present. Therefore, if a watercraft has been in such a body of water, it signifies an increased likelihood that it may harbor these species, thus warranting a more thorough inspection.

The other options highlight scenarios that do not directly correlate with the specific high-risk factors established for inspections. For instance, simply being unused or being a newer vessel does not provide any information regarding the vessel's exposure to invasive species. Thus, the context of recent travel to a high-risk waterbody is the key factor that determines the necessity for a high-risk inspection.