In the end it is still subjective since I am judging yes ;p
It should be somewhat possible to detect plagiarism with a bot, but also in that case there can be false positives. A lot more professional photographers are joining the eco system and they tend to share on multiple platforms and have their own websites as well.
Yes, that would be a huge problem for some of us, because I have images with stock agencies and art sites. My images are also being used all over the web (sometimes legally, and sometimes not) but a bot could find one of my images on say WEb MD (legally paid for) and assume that I was stealing the image from there!
I want to follow this race, but I do not understand how, I have a lot of interesting photos, because I am a photographer from asia, thanks his enlighteners