@fmsfms, the second an attractive man ignores my boundaries, my sense of attraction to him evaporates.
Men are allowed and capable of approaching women without it being harassment. I liken it to being in a shop, everyone says "no" when approached by a salesperson,
NO NO NO. When I walk into a shop, I do so by choice, and I accept the really annoying, anxiety-triggering salesperson as the cost of that. Also, the salesperson does not want to date me or ~~have sex with~~ rape me.
I do not have a choice about getting on the bus or train (I have to travel), or going to the supermarket (I have to eat). I DO NOT WANT a man to approach me with sexual or romantic intentions at those times. I do not want a man to approach me in public, unless he is asking for directions or telling me that I've dropped my shawl, or has a similar non-sexual excellent reason.
If a man attempts to flirt with me or preposition me in public, he has already crossed my boundaries and I have said and will say "FUCK OFF CREEP" very loudly. If a man attempts to flirt with me or preposition me in public, that is already harassment. I am not public property, my body, mind, and time are not up for grabs. I do not owe you a polite refusal. I do not owe you anything, you imposed on me.
Because of bad experiences with assholes like @fmsfms, my default response to a male trying to get my attention in public is "ignore", followed by "FUCK OFF CREEP" if the male persists. This harms the men who just want directions.
My first bad experience was when a drunk prepositioned me on the way to school. I was 13, and in school uniform. Men are a hazard to me and I will vet the hell out of them before letting them in my life.