The sign was from a member of the Canadian Armed Forces asking the Kings' centerman for a puck in exchange for one of his military patches.
Danault agreed as the two shared a nice moment before the game was underway.
Earlier this week, the former Canadien spoke to the media about the encounter.
"Yeah, I think I definitely won that trade," Danault said half-jokingly. "It was a great moment. You don't expect that, you don't expect to live those moments, but yeah, I just saw my name on his [sign] and said, ‘If you score three goals, I'll give you a souvenir and give me a souvenir, as well.' So, I just gave him the puck. I wish I could give him a stick but it was the moment I got caught and I gave him the puck."