Compared to Judaism's regular dietary laws, the rules for being Kosher for Passover are decidedly stricter. Not only is the punishment for consuming chametz the more severe karet (Ex. 12:15, 12:19), but the chametz is prohibited even in trace amounts (B. Pesachim 30a). Considering how strict the Jewish community is regarding keeping a kosher kitchen, it should not be surprising to find even more stringencies when it comes to the laws of Passover.
One problem we find with stringencies in Jewish Law is the tendency to confuse the additions with the actual to the point where being confronted with halakhic sources can be jarring to people who might not know any better. I wrote about one such example several years ago, and I recently came across another misconception common enough to be worthy of discussion.