Some SXSW Interactive attendees got an unwelcome surprise when they reached the airport to depart for home.

Several flights have experienced unexpected delays at Austin Bergstrom International Airport due to swag, or promotional items, in checked suitcases setting off alarms. It’s not been confirmed how many flights have been affected.

SXSW is a haven for marketers, and attendees leave with bags packed with everything from bulky electronics, like speakers and cameras, to basics like T-shirts and tote bags.

Initially, the ABIA reported that inks on certain magazines were registering as bombs. However, officials later determined that Transportation Security Administration agents aren’t able to determine what’s in some densely-packed bags going through screenings. In those cases, security agents are forced to go through those bags by hand, item by item.

The ABIA recommends that airline passengers leaving SXSW pack promotional items in their carry-ons to get through security more quickly.