Thank you.
This subamendment pertains to the ambiguity that can be derived from a person's fear on reasonable grounds. It invokes a legal test that is usually used, which is reasonable and probable grounds. It strengthens it rather than basing it on fears. It looks at the individual's beliefs.
Fears, as you know, are very subjective. People sometimes have irrational fears based on situations, including a person's race, etc. I think this is a more neutral term that still encompasses the intent of the clause.