Yes, a mother asked me this today. I was ending up an event at the mall. A family was lingering even though we'd let everyone know we were closing up. Pushing a stroller back and forth with a crying child who looked around 5 years old.
I didn't pay too much attention because I was busy packing up. I did hear them tell the child that she couldn't get any face paint and with this the girl would wail louder. Next thing I know the mom comes over and says, "Can I just stick my finger in your paint?" I was confused and wondering why she would want to do that. I was thinking to myself, "No." but didn't say anything out loud because I was trying to avoid being rude. She said she wanted to stick her finger in my paint, to just put some paint on her granddaughter to make her happy.
Then she asked me if I could just paint something on her... ANYTHING. I told her I couldn't, (I'd already turned away other people) but told her I had an extra balloon puppy that she could have and if she thought that would make her happy. She said, probably not, but took it anyway.
Heading home I thought I have to share my little experience of a parent wanting to stick their finger in my paint with the chat board. Ha.