Can I replace "I don't want you getting lost" with "I don't want you to get lost"? (I only knew the latter one with to infinitive.) If both can work in this situation, how should I decide which one to use?
Native speaker’s answer
You are correct! Both "I don't want you getting lost" and "I don't want you to get lost" can be used here. They both refer to something the speaker does not want to happen (the students getting lost) and are actions that have not occurred yet. In similar situations, it is up to you to decide which tense to use. There is preferable answer, however, using a -ing verb can sometimes sound more natural when speaking. Ex: Put on a coat! I don't want you getting sick. Ex: Stay close! I don't want you to get lost.