A major disadvantage of mechanical guidance is:

The statement that performers can become reliant on the equipment is a significant disadvantage of mechanical guidance in skill development. When athletes or learners frequently use mechanical devices to aid their performance, they may not develop the necessary physical skills or muscle memory that are crucial for performing the activity independently. This dependency can hinder their ability to execute the skill without assistance, making it difficult for them to adapt to situations where the equipment is not available or applicable.

In contrast, options discussing ease of understanding, affordability, and applicability to all skill types do not highlight the fundamental challenge posed by mechanical guidance. While some learners may find mechanical guidance straightforward, if they become too reliant on it, it can detract from their overall performance ability. Moreover, not all skills can be effectively taught using mechanical aids, as some may require a more nuanced approach that emphasizes personal technique and judgment. Thus, the reliance on equipment can greatly limit a performer's development and adaptability in the long run.