Is not owning up to your mistakes the same as lying?

I do stuff all the time but I don’t usually own up to them so I always get away with it because people never realize it’s me. For example my coworker found a phone in the bathroom at work but just left it there. Then she told my coworker and she said “why didn’t you give it to a manager?” And I’m wondering myself why she said she found a phone in the first place if she was just going to leave it in the bathroom. I just don’t own up to my mistakes unless directly asked because I feel like I just look foolish for telling on myself.