I wouldn't have a worry about it in certain circumstances, ie: if my child really needed it and the person providing the feed had been screened etc.

I recently found out that my mother did this for someone - back in the 70s. I met someone recently who knew my mother back in the 70s/80s when we were kids. She was going on about what a wonderful mother my mum was and how there were always kids around but mum could always put on a good spread.. then she related a story about a time when a man turned up at the door with an infant and hurled the child in Mum's arms for care/feeding. Apparently the man's wife was really ill and he had no idea what to do with the child so mum ended up wet nursing him for the weekend. She obviously had one of us as a breast feeding baby at the time. I was astounded as I had never heard the story before! I have of course heard of wet nurses, but that was in Victorian times in my mind.

When I asked mum she said it was because she was a member of Nursing Mothers Association and the mother who was ill had sought out the association to find someone to look after her baby while she was in hospital. I was really proud of mum when I heard this story, well I am generally, but thought this was rather cool! Based on this story, I think it is a wonderful thing to do.