The Seahawks have their own history with doctored balls, as anyone here in Dallas remembers.
Seattle K ball conspiracy theory still lingers
http://espn.go.com/blog/dallas/cowboys/post/_/id/4697590/the-curious-case-of-the-k-ball-vs-seattle
They probably covertly replaced the balls with remote controlled balls, which can inflate or deflate on command as well as homing in on sensors that were stuck on Seahawks helmets.