Mature Content Filter

What is the Listal etiquette regarding asking that the mature filter flag to be set on a list?
I know most of the time this is like spiting hairs especially since pornographic images are not allowed... still... there are a few that I doubt my mother would enjoy viewing if she were to visit the site.
Would you ask the person directly? (Which hardly ever seems to go over well)
Is there a thread where we can post list for staff to consider?
Which would still be out in the open and wouldn't feel quiet so sneaky or drastic as 'reporting' a list.
I know most of the time this is like spiting hairs especially since pornographic images are not allowed... still... there are a few that I doubt my mother would enjoy viewing if she were to visit the site.
Would you ask the person directly? (Which hardly ever seems to go over well)
Is there a thread where we can post list for staff to consider?
Which would still be out in the open and wouldn't feel quiet so sneaky or drastic as 'reporting' a list.

Don't see whats wrong with suggesting someone set their list to mature content.