The Willful Ignorance Doctrine

In case it is used as a defense, there is legal precedent addressing the issue. Per Alexander F. Sarch:

"When a defendant is charged with some crime requiring knowledge of some fact, but the defendant deliberately avoided learning whether the fact in question obtained, it is common practice among federal courts to give so-called willful ignorance instructions.  Such instructions tell the jury that it may find the knowledge element for the crime to be satisfied by the defendant’s willful ignorance of the relevant fact (also called the inculpatory proposition)." 

Furthermore, "the Supreme Court and all federal courts of appeals have adopted a version of this doctrine in one form or another.  On one hand, certain of these appeals courts require proof of an existing motive for remaining in ignorance besides proving the elements of (1) having suspicions about the fact of which knowledge is required; and (2) deliberately refraining from investigating the existence of the relevant fact."