FIRST and foremost do not step into the office without a steward.
If they say you do not need one ask the following question with a witness present:
Is it possible that this meeting COULD result in discipline?
If so demand a steward before answering any question.
On second thought they already implied discipline might be forthcoming, so demand a steward and don't answer before one is there. Review what happened and any words spoken with the steward before going in. Don't answer any questions before going in, demand a steward.
When in the office with the steward, allow him to answer as many questions as possible. Don't answer yourself if possible.
They will try to trick you by asking non-threatening or unrelated questions before asking questions that implicate you.
They will attempt to get you to contradict yourself...dishonesty. Take a lot of time answering, careful not to fall for leading questions. Point out any errors in their statements or questions. Be truthful, don't speculate, don't rush. "I don't recall" is an acceptable answer. You can remember later and not contradict yourself.
Any time you do not know how to answer a question ask for a private talk with your steward before proceeding, and step out with him. Do it as many times as you want.
-10 seconds is more than enough time from stepping into the truck to moving the truck...I believe 6 seconds is the standard. So on that point ask for more training if you are truly that slow.
-Avoid backing as much as possible.
In your defense, with the steward present...he should ask these questions go over these before the meeting;
-If he videotaped you backing several times without honking...Can you hear other truck sounds on the audio?
-How far away was he when he videotaped? Is it possible he was too far to hear or pick up the horn on the microphone ? Ask for specific distances, specific locations where he was parked when he observed you, and where you were.
-If they say you should have avoided the backs...Was it too icy to safely walk?
Does he know that the package was light enough to carry? Ask him if he knows the weight of the box he observed you delivering. If not, did snow/ice rule out using a two wheel cart?
-Is this the first occurrence of observing you not honking?
The most you will get is a warning letter for not honking. Grieve all discipline. I have received enough warning letters to wallpaper my bathroom. Who cares? Grieve the discipline anyway.
And make sure you do everything by the book.