Question: can you connect someone else's airpods to your phone?
Answer: Yes, it is absolutely possible to use someone else's AirPods. The issue you'll need to deal with is pairing. When AirPods are paired, they become “X person's AirPods” and that's how they show up in your device list. If you take “X's” AirPods and use them with your device, they'll be renamed as “Y Person's AirPods”.