Would you give your frequent flier miles for a free international ticket to a friend of your sister's?

My sister lives in Poland. I offered to give her sister my frequent flier miles for a free international ticket to come visit me in Utah. She declined. I told her that I wasn't sure if I would end up using the miles before they expire, so I would still give them to her if she wanted to go somewhere else. She then followed up the next day and asked me to use my miles to get a ticket her friend from high school to fly from Pennsylvania to Poland. I told her no.

I told her that I would give it to a family member or close friend of mine, but not to a friend-of-a-friend. I didn't think that her friend would feel comfortable accepting something worth over $1000 from someone they don't know. She says that her friend would accept it and that no one would sit around thinking about the monetary value of a gift. Personally, I wouldn't accept something expensive from anyone other than my husband. She thinks that I am cheap and selfish.