if your text paragraph styles don't use "keep baseline" option:
==> your document default text frame could has some bottom inset set (text frame options settings)
if your text paragraph styles use "keep baseline" option:
==> your document baseline grid could be modified to jump up by some space ("baseline grid start: " in Preferences), so the last grid would keep proper distance from a bottom of page.
I take it you are printing on a device like a copier or desktop printer that has a non-imaging border of some sort.
ID really doesn't know anything about the printing conditions, and on a press this would be a non-issue, just as bleed is a non-issue on press. It's up to you to do your documetn setup in such a way that your file will fit the output conditions. One way to do that would be to set a bottom margin that is far enough inside the page that descenders stay in the imagable area. another would be to add bottom inset to the text frame, as Jump_Over suggests, but I'm not terribly fond of that since a manual adjustment of frame height would carry the inset along for the ride, and I'm even less fond of setting the type to require alignment to a grid becasue it's pretty inflexible.
Any creative solutions that do not require a lot of manual action by the users? Having them manually adjust the text frames seems quite silly considering how sophisticated InDesign is.
Are you by any chance familiar with the acronym PEBCAK? If you have control over the templates your users are using, you can define the Basic Text Frame object style to have some inset at the bottom of the frame. (I found the handy add-bottom-inset solution here, with the Google search terms "indesign descender outside of frame".) But there is nothing forcing your users to use the Basic Text Frame style, or even from editing said style themselves.
I can imagine a wide variety of solutions to this issue - another approach would be a Preflight Profile that had the "Bleed/Trim Hazard" option checked, and that had aggressive settings for "Bottom." But none of them are foolproof (i.e. users can turn Preflight off), so the root of your issue must be addresssed with InDesign operator education.
Whoops, never mind my Preflight suggestion. <sound of palm smacking forehead>
But the sociological user-experience stuff is still valid, I think.
> Having them manually adjust the text frames seems quite silly considering how sophisticated InDesign is.
I'm not sure what this means. Surely any templates or example files you provide to your users have no overly large text frames, and thus they *choose* to enlarge them "manually"?
To help myself and colleagues remember Real Important stuff, I type it out as text, in a big bold font, coloured bright red, and on a layer of its own. *Then* I: (1) set this text frame to non-printing; (2) lock the frame; (3) set the layer to non-printing; (4) lock the layer. It's pretty hard to accidentally miss *all* of those little non-verbal clues :-)
For the text, you could draw a line and write under it "Do not cross this line, or suffer the consequences."
@Jongware – and then one day out of the blue, someone is working on after accidently hitting "y" instead of "v" allegedly using the keyboard shortcut for "Paste in Place".*
And from now on is missing all those good intended hints ;-)
Until the time, the same accident will happen again ;-)
* on Mac OSX:
"alt + shift + cmd + y" = Overprint Preview
"alt + shift + cmd + v" = Paste in Place