bullcrap. it's should be perfectly legal to use image ID sites. it's just the matter of the user making sure the image is unidentifiable via reverse image search.
This is 'guess' the anime, not 'identify' the anime. So yeah, I'm with froody here...
As for vagueness..
2. Content in a picture must be 100% identifiable with only one anime!. So Tokyo Tower or a picture of Tokyo destroyed is not allowed!
if Tokyo Tower is not allowed, more so random buildings...