Is this permissible in a classroom setting?

[MasterOfNone]

The wording still leaves this open to interpretation. Does "in plain view of another person in a public place" mean "in plain view of another person (while YOU are) in a public place" or "in plain view of another person (who is in) in a public place?" The latter would mean that if you can be seen from a public place, you're in violation.

Interesting thought, but I don't see how the latter would fly. As I recall, Charles has said (paraphrased, of course) that the CHL laws grant CHL holders additional the "privilege" (which we all know should be a right) of carrying a concealed firearm in public, with certain limitations, but that those laws cannot/should not restrict us from doing what non-CHLs can do.

So if the latter (in your example) were the correct interpretation, then a CHL holder could not OC on their property if they could be seen from the street or other public place (no more OC while doing yard work). Yet a non-CHL would be able to freely.

In one's own front yard, carrying is not "under the authority of Subchapter H, Chapter 411" so (a) would not be applicable.