Enforced: The writers write Linda weak thinking it will humanize Harry.
Lampshaded: "We have to go save Linda again?"
Invoked: Linda is a spy and wants to leave with the intelligence without raising suspicion. She phones it in enough that they'll be glad when she leaves at the first safe place recognizing that she isn't making things better.
Defied: Linda never goes into conflict with Harry, she knows it'll cause more problems. Or, in reverse, Harry refuses to let her come along because he knows she won't be able to handle it.
Linda asks to be trained so she can be able to handle things on her own.
Discussed: "Oh crap, Linda's here." "I know, how long before she breaks a heel and we have to carry her again?"
Implied: There are two versions of events. One has Hiro's forces rescue Linda and one where she is already dead. With her alive three of his squad die. With her dead no one dies. Hiro's anger could explain it as well though.
Linda's insistence on going into these dangerous circumstances are very telling about his relationship.