The Talmud discusses a case in which one prepares one’s house on the night before Passover and then a weasel is suspected of having brought in a piece of bread from another house, or even into one’s city from another city.
The sages conclude there that it would an endless task to observe such stringency.
Apparently, it is not an endless task for some who wish to be more kosher than kosher and rule that a wind-swept seed of barely falling into a field of quinoa makes it prohibited on Passover.