I think the tags are kind of like a bracelet at theme parks to prove that you paid admission. Just a guess. I think it's cute how Ms. Song likes Grandpa. Old people love is just freakin adorable.
What exactly does Suk-Hyun feel for Young-Shin/ Bom, does he feel guilt, love, or a combo of both? Even though I think he is/was a jerk at least he feels guilty. That shows he has a heart! No matter what heartless decisions he made.