No, not necessarily! If you're caught "red-handed" and there is clear evidence of a violation, whatever it is, and they have you by the "short-hairs", you then say you're sorry and vow never to do it again. THEN DON'T EVER DO IT AGAIN!
As a retired steward, I handled many cases like this. The company had the employee dead to rights. We recommended leniency and job back. They always got it. Of course, there are more details in all these cases to be heard but the point is...if they "got" you and you deny...then you're guilty of now, "LYING". You want that?