On Awful Movies wiki I suggested that quotes in the infoboxes should be as professional as possible, just like the pages in general. For this reason I removed preposterous quotes from Open Season and a few others.
It's difficult to state criteria for this, since quotes are subjective. I'd say to leave the decision to the one who makes the page but there is always the chance the creator of the page can out a tasteless quote that must be changed.
Anyway, I noticed this issue too and I really think it is prime stuff for edit wars. Do you think the only solution would be to remove the quotes from the code of the infobox? Because there is no way to make only the template uneditable after a good quote is put.