The Code Breaker's Secret

I recently got a promotion at work after years of hard graft. During the team celebration dinner, I couldn't resist ordering an extra round for everyone on company expenses, we all had a blast and no one complained. But as I was leaving, I saw our finance manager taking notes. Is it wrong to feel guilty about a little fun, or should I just own up that sometimes bending rules leads to team spirit? What do you think is the right call here?