I depends on what the networks have been trained to recognise - if they have been trained to recognise images of dogs then they are more likely to detect dogs i

I depends on what the networks have been trained to recognise - if they have been trained to recognise images of dogs then they are more likely to detect dogs in clouds. See also https://news.ycombinator.com/item?id=9818077 https://news.ycombinator.com/item?id=9818077 . And see also https://news.ycombinator.com/item?id=9736598 https://news.ycombinator.com/item?id=9736598 for more background to the topic.