This is something you hear about every now and then. Some cultures other parents and even grandparents will nurse other peoples children while they watch them. I saw another person once freak out because she found out her husbands mother let her baby nurse on her breast for comfort.

What kind of feelings do you have about this kind of thing?

I think it's weird, but I am able to understand I was raised in a culture where even the MOTHER nursing her child can cause a ruckus because some joe at burger king got upset about seeing moms breast. Surely he ran to the beach the next day, whooped off his shirt, and made everyone else around him witness his man boobs with complete impunity. Can you tell I feel SO sympathetic for him?
So anyway, I can let it go and try to consider that it really is far more comforting for the infant. But I don't ever want to find out my son's grandparents popped their boobs in his mouth. lol