"Condone Untidiest Thefts" feels like an effort to get Allison Knight back into the action. It's very convenient that she happens to be friends with the sister of the team's prime suspect Patrick O'Malley and that he'll only talk to her. Plus, when she tells Weller beforehand that it will be fine, that's TV's universal sign that things will not be fine.
Allison wasn't a likeable character before and she isn't now, constantly arguing with Weller on both the professional and personal fronts. Even if you set aside the plausibility of her being able to be involved in the case given her