Law Students Donating Canned Food To Get Immunity from Being Called on in Class:

At various law schools, student groups organize what are sometimes called "canned immunity" drives — if students donate canned food that will end up going to a soup kitchen or some similar charity, the professors agree not to call on them. I've always been vaguely uneasy about this, but I'm not sure whether I should be.

Before people start bringing up general libertarian arguments, note that the question isn't whether this practice should criminalized, but rather whether there's something improper about it that should lead me to decline to participate. What do readers think?

UPDATE: I inadvertently omitted an important fact, though fortunately many commenters filled this in -- this drive lasts a day or two, as does the potential immunity from being called on.