[panzagl]

Probably a US high school, where off-campus lunch is usually reserved for older students.

[JCattheATM]

That's fine...never heard high school grounds referred to as a campus before so assumed college.

[jhbadger]

This is fairly common in warmer climes in the US like California. Rather than have a monolithic high school building with lots of wasted space for hallways they will have a bunch of smaller buildings that students go between outside. They are "campuses" in the same sense that various tech companies call their cluster of buildings a "campus".