Are women's breasts that ugly that they must be kept hidden? And so what if someone sees a topless woman? Will the child turn into a pervert in the spot or something? Besides children have already seen breasts: on their mothers, especially when they were breast fed (yeah, they likely can't remember that, but I'm trying to make a point). They don't have their sexual drives developed yet (that's puberty and teenagers), so its not like they can get anything naughtier than "lets use markers on them to make faces".
If anything, actually seeing breasts will remove their mystery: their just lumps of fat with nipples on the end. Men have nipples too.
Question: Should the women consider the "rights" (for lack of a better word) of others when going topless in public?
I would say that from a more feminist point of view, yes. A woman should not allow other's judgement to tell her what she can show of herself and what she can't. She has/should have the right to show what she desires of herself.
The opinion that's more mine, says: what rights? Unless the woman needs to put on clothes for a very practical reason (whether environmental or other) or for some reason can't decide for herself, why not? Some like the view and it turns out that most people aren't that beautiful naked.
Do people who are offended by exposed titties have the right to make the topless women cover up?
Not more than anyone else has the right to tell anyone else what they're wearing.
What should topless etiquette be in a public area where there's children, families, and people of all sexes & ages?
If you don't like what you see, don't make a scene and instead just go to a beach (or a section of the beach) that does not have topless women.