We've lived in our house for 4 years and in all the time we've lived here I go outside to smoke, round the side of the house where my DH has built me a little smoking shelter 
.
Last week, during that little burst of lovely weather, my neighbour knocked to ask me to stop smoking round the side of the house, as their conservatory and back bedroom smelled strongly of cigarettes. I was a bit 
that this had never been a problem before, and smoke from my 3 cigarettes a day was floating across our two gardens (there is probably about 20 metres between our houses) and making its way into their house but agreed that unless it was raining, I'd go to the bottom of our garden for a cigarette in future.
I've just been hanging washing out. The neighbours car isn't there so I presume they're out somewhere. As I walked down the side of my house I could see their daughter through the gaps in the fence, standing at the side of their house, puffing away. She is about 12/13 years old. Their conservatory windows are open. She is no more than a couple of metres away. This is clearly what's causing their house to smell.
Whilst I don't want to drop her in it, I don't want my neighbours to think I've ignored their request, and if it were my DS I'd want to know.
Would you tell them?