Are you stalking?!
Should be the appropriate response, but they will probably just ignore that and act as if it's perfectly fine to follow them around and take pictures of them.
what exactly the lil girl is planing? to go as far as taking a picture of them it cant be good... for what is worth i dont think he has interest in other girls. But i feel some shitty drama incoming.
Also, sometimes ive wondered if Kazoe didnt started all this research partialy as an excuse after already being interested in him.