“once I had a student who was always wearing the “wrong ” socks 9ie socks which the school didn’t allow) I bought her a bunch of permitted socks and wrapped them in nice paper and each day left a different pair in her locker with a funny note. Problem solved with out a word of tochacha. A year later we had a follow up discussion whith no anger and today this girl is married with children of her own and she always wears socks and is very tzanua. What would have happened if I would have punished her? yelled ? lectured? ”
The way you handled this was really good. I think if you had yelled or lectured the girl, she would have been turned off, upset, and more likely to break halacha. But instead you made it into a positive thing by gifting her the socks, and set her on the right path!