I don't think high reputation has any effect, nor stealing or getting caught. Drop way TOO low in rep, though, and she'll leave. Don't worry, it has to be very very low...all the other goodies leave before she will.
Oh and get her a suit from the Brooks Brothers guild, matches her style.
BTW, never heard Aerie bicker with Jaheira over you before until the last week...WOW! Her stuff was mean/hilarious about Jaheira--my brother is playing BG1 on his mac right now and I can definitely see the kind of character Khalid was, whom Aerie mentions in one truly extended retort. Worth it for the insults/truths thrown about! It's too bad they couldn't have them argue on all the way after you've picked your one "true love." Voice talent and script are amazing.