On another thread, buttermarc wrote the following:

Failure to disclose is just as dishonest as a seller auctioning off a PRO-graded card that he or she knows is trimmed. There may be a bit of a differential between a collector who does not necessarily know the card is trimmed (more often the case with Topps than OPC issues....) as opposed to the dealers (there are at least two that come to mind...) who actually do the trimming and submitting.