Is there some sort of legal document that I and my client can sign that will indemnify/protect said client from lawsuits, and make me legally responsible, if I accidentally use a piece of footage or music or audio in the wrong way?
And if this document exists, has a client ever been penalized in spite of having signed this document.
[Justin Cordes]"Is there some sort of legal document that I and my client can sign that will indemnify/protect said client from lawsuits"
I think that the word that you are looking for is called a "contract". And yes, even if a client has signed said document, ignorance will not protect them. I.e. one would expect your client to use your production as part of their public marketing/training/PR materials and if it was to contain something obvious, like a piece of chart music, say Lady Gaga or a clip from the latest hit TV series, say Sopranos or True Blood, then they are responsible for distribution. And if they haven't satisfied themselves that you had the rights to use that material, then they could be deemed guilty.
Take the case of Viacom v Youtube. As much as Youtube is not the "producer" they are the point of distribution/publication. Since Viacom is not going to gain much from suing a spotty 14 year old and their poor parents, but are likely to get more from a Google, then this made a natural target. The same goes for a one man band video producer working for a multi million dollar client - if your copyright had been breached, who would you go to for damages?
So it would be ignorance on your clients behalf to believe that a document would indemnify them from lawsuits, unless that document explicitly said that and stated all copyrighted materials had been cleared for release. In that case, it would come down to the honesty of the production company, i.e. you.
You can't prevent anyone from being sued. You could state that you would cover legal expenses and all civil penalties and damages as the result of such suit but if they know you don't have the ability to cover that as "small fry" then the paper wouldn't be of much value.
First, I'm not sure if you're talking about something that will be for a corporate use or something that is destined for television broadcast release.
In terms of network television production, yes there is an indemnity clause that usually a part of every contract that is signed with a production company.
It essentially says that if someone decides to sue the network due to something that was in your program, you will be held liable for any damages that result from this suit and the network will essentially drag you into the lawsuit. In some cases, their lawyers will be able to extract the network from the suit leaving you on your own.
This is why it is so important for anyone doing production to look into Errors and Omission Insurance which covers you for this very situation.
Also curious what defines "used in the wrong way" in your situation.
Walter Biscardi, Jr.
Editor, Colorist, Director, Writer, Consultant, Author, Chef. HD Post and Production Biscardi Creative Media