If it is an artform, it is producing bad art.

It also is circular reasoning: It is suspicious because it is.

I am reminded of a tired cliche that use to inundate American television dramas in the 1970. The script trotted out a 60ish married male character and placed him in a restaurant having a candlelit dinner with a very pretty, 18-year-old female who was not his wife. There is giggling and laughing and then the man would present the woman with a gift, usually jewelry. Next, one of them kisses the other on the cheek. The story would then focus on this man and who was that woman he was with that wasn't his wife and they would spin the suspicion that he was having an affair until the big reveal: he took his granddaughter out for dinner on her birthday and gave her earrings as a present followed by a kiss on the cheek (or she kissed him on the cheek out of gratitude) and isn't everyone just horrible for thinking the worst of the man. Tsk, tsk.

Like photography in airports, no one knows why it is suspicious, but why let facts stop people from thinking the worst of innocent people doing nothing more than enjoying themselves?