Aang knows a Capitolite when he sees one. Off-worlders and Districters hold themselves differently than Capitolites. Nonetheless, a person being a Capitolite isn't an immediate reason to dismiss them, especially if they have tape for your bat.

"Great!" He adjusts his hold on the bundle in his arms, and gently moves the cloth so he can reveal the bat's head. She squeaks softly in protest. "Hariti's wings are hurt. I could probably splint them with pencils until I find something better."