Co-showrunner, Todd Slavkin. responded to a concerned fan with, “We are aware of auction but had no idea about spoilers.
While most of the props up for grabs were of the generic, unspoilery flavor, some of the swag inadvertently revealed major plot points for the upcoming final episodes.
In particular, a detailed letter from Clary (Katherine McNamara) to Jace (Dominic Sherwood) outraged spoiler-conscious fans and sent the hoards to Twitter to make their concerns known.