When dd1 was one I had a friend round whose dd was nearly three and fully toilet-trained at the time. She asked me if her dd could do a wee in my garden, as this was what she would do at home when playing outside. I said 'not really' and I think the look on my face said it all. My friend thought I was being silly and that I would know better once my dd1 got older, but now my dd1 is three and toilet-trained herself I still wouldn't dream of letting her pee in my, let alone anybody else's garden - I would only let her wee somewhere other than on a toilet in an emergency.
What about everybody else?