Take the jelly bean prayer up above. That was sent home with RD Nadine Devine's Junior Kindergartener in honour of Easter.
WWJD? Not that.
Or this needs-to-be-seen-to-be-believed note that was sent home with another friend's 5 year old.
I imagine that the teachers responsible for those two examples don't see either as unwise as why question normal behaviours? If everyone does them, they must be ok.
Yet I'd wager that if those same two Kindergarten teachers reflected on the lesson their use of classroom junk food is teaching their incredibly impressionable, young, students, they would recognize that teaching incredibly young children that it is normal to reward even the smallest of victories or celebrations with junk food is not in their students' best interests.
Teachers, if you're reading this, so far as rewarding kids go, it's not difficult to do so without candy. Extra-recess, dressing your teacher up in funny clothing, being in charge of school announcements, a classroom dance party, have a class outside, hand out "no-homework" passes, stickers, bookmarks, etc...
I know that teachers care deeply about their students, which is why I genuinely believe that putting an end to junk-food classroom rewards is something that society, and teachers, can fix.
[And for some suggestions as to how you might begin to approach this with one your children's teachers, coaches, whatever, here's something I wrote a few years ago about shutting down your children's sugar pushers]