Accidents happen.

When bad things happen, it can be very hard to deal with. We might become very sad or angry. These feelings can be worse when we don't know who's fault it is or why the bad thing happened. Sicknesses like cancer can cause a lot of pain to entire families, and often there is no one to blame and no satisfying reason why.
Sometimes, though, people do bad things and don't take responsibility for them. The person may be mean, but probably they are just afraid of getting in trouble. It's very important that we take responsibility for our actions, though. Otherwise we are causing someone else that sense of faceless anger or sadness.
If we cause an accident and something breaks or someone gets hurt, but no one sees us actually cause the accident, do we get away with it?
No. We will know, and that knowledge will grow inside of us like a cancer, causing lots of other problems we may not know about until it's too late.
Honesty is not just telling the truth when asked, it's being active about taking responsibility for our actions.
If we cause an accident and something breaks or someone gets hurt, even if we don't get caught, we need to take responsibility somehow.
We could look for someone who might be related to the accident so we can explain what happened.
We could leave a note at the scene of the accident explaining what happened, with information on how to contact us so that we can take responsibility.
or
We could hide it away in our hearts and carry it around until we get comfortable with the weight of it and forget that it ever happened and carry waves and waves of these tiny weights around in our heart, slowly dragging us down into a dark distrust of other people, alone, cold and wondering why.