I suppose it's similar to the discussion older and more successful men have about avoiding "gold diggers", "bear traps", and "black widows". Not all women are after a man's money, but those that are will actively seek out such men, so you'll never be safe. One wrong move and you're suddenly working overtime the rest of your life to pay child support for a child conceived without your consent. Whereas, a bear would only run into us by chance, and would be more likely to leave us alone if we dropped our food and calmly walked away.
Edited note for clarity and posterity: Stereotypes are always hilariously offensive - I think some people just learned that.