No, this has never happened to me.
But one night, on my way home from the pub, I had a sudden desperate number 2 urge, and as I could hear people not far behind me, I let myself into someone's back garden and did the deed. Looking down on the floor after pulling up my trousers, I could see nothing, and was too drunk to investigate further.
The following morning, I couldn't find my wallet, and had to walk back to see if I had dropped it when I'd dropped my trousers to pooh. The owner of the house appeared in the garden and asked what I was doing. I said I was sorry, but a friend had run off with my wallet and had said he'd thrown it over a garden fence.
The man said he hadn't found any wallet, but some a-hole had been in his garden some time during the night, and had shat on his tortoise, which he'd discovered first thing looking like a Viking's helmet!