I'm not penalizing them. I don't think it is bad if someone is a Leetcode junkies. Definitely not downing points if they use Python.

But to actually answer your question. Say the role is in JavaScript, say a Frontend role and the candidates want to answer it in Python instead of JavaScript. Then it is possible that the candidate is a Leetcode junkies.

Why I know? Because I do this myself. And definitely no points subtracted from knowing and using Python.