This doesn't seem like that big of an issue unless you're cheap. Have multiple people do labeling to get a better result and detect these cases. You can also

This doesn't seem like that big of an issue unless you're cheap. Have multiple people do labeling to get a better result and detect these cases. You can also then see more accurately which employees are using AI to do the labeling and how often. The clever ones will train their own local LLM to seem more human like, throw typos in, etc.