Answer:
Yes!!!! Even if the person isn't having any symptoms, it is possible to catch that horrible virus. If they have a active cold sore and you share a cigarette, you will get it for sure. It can't be cured and is highly embarrassing. Definitely a cute girl deterrent! So do not pick up and smoke cigarettes you find on the ground whatever you do.
Theoretically yes, but it's very unlikely if they're not showing symptoms. It's exactly the same risk as kissing the person - best to avoid it if they have a cold sore, but if they don't you're highly unlikely to catch herpes from them.