Rick Grimes (Andrew Lincoln) is as cautious as you get. That is why in the Season 4 finale, Rick was smart enough to bury his bag of guns outside of the Terminus fences before entering the cannibal-infested safe haven. Rick would later dig up that bag in the Season 5 premiere, "No Sanctuary."
On the Season 5 DVD/Blu-ray commentary track, The Walking Dead showrunner Scott M. Gimple revealed that he slipped a personal note to Andrew Lincoln in the hole. He did this because they had planned to dig up the bag from same location when Season 5 began filming, but for whatever reason they filmed the bag's retrieval from a different location, which means the note is still buried somewhere in Georgia.
"What I had done," Gimple explained, "I had buried a note for ourselves when we put the dirt back in the hole that Rick had dug, because Andy did want to dig the hole. And then we wound up shooting this in just a slightly different place. And that note is still out there somewhere."
"Oh my goodness," Executive producer Gale Anne Hurd responded on the commentary track. "There is going to be a scavenger hunt to find the note! I hope it's a note you don't mind if people read."
"It might be a little corny," Gimple said. "That's about it."
(via Entertainment Weekly)
The Walking Dead's fifth season comes out Aug. 25 on Blu-ray and DVD and features more than three hours of bonus features including the clip, above. Season 6 premieres on Oct. 11.