Which of the following is NOT a visual cue that a synthetic line may part?

When assessing the visual cues that indicate a synthetic line may part, it is important to recognize the significance of each choice presented.

A frayed line is a clear indicator of wear and weakness, as the fibers have begun to break down, compromising the integrity of the line and suggesting an increased likelihood of parting. Observing excessive load on a line, such as when it is being pulled beyond its rated capacity, serves as another direct visual cue suggesting that the line is at risk of failure.

Seeing a shiny appearance on a synthetic line often indicates that it has been subject to friction or wear, which can weaken the line over time. However, when discussing two blocking, which refers to the situation where a line is constrained or pinched between two surfaces, this does not inherently provide a visual cue related to the line's impending failure. Instead, two blocking is a procedural issue that arises during operation rather than a condition observable through the line's condition itself.

Thus, while fraying, excessive load, and shine offer tangible visual indicators of potential failure, two blocking does not serve as a visual cue for the line parting, making it the correct response to the question.