PY is right on target (especially his joke).
There IS such a thing as a casual hello. I give it many times each day. I never had any wrong intentions when I say hello to the train conductor; nor do I when I say hello to the 50 year old woman and her granddaughter (though in truth, I avoid saying hello or GS to young BY girls because it embarrasses them due to what they have been taught). I have ALWAYS said GS to the 50 year old woman, even going back to when I was 10 (was there ever such a time?). And I have NEVER taken it as anything more than casual, polite greeting when she returns the hello. I guess it goes by what we are taught to think of it – if we are told it can lead to improper relationships then that is what you will think is happening when someone greets you.