I have a client who used a licensed script as a foundation to their site. They paid for the license and it is a lifetime, single-site license. There are no more details than that concerning the license on the script website. My client just asked me to remove any mention of the script name from the code as well as the logos and footers visible to the user. I can understand removing the visible branding, but I'm a little wary to remove the copyright statements in the comments of the code. What are your thoughts?
NOTE: I am not and have never been an attorney. I post merely based upon my own experience over a freelance career spanning a couple decades. For legal advice, it is always best to speak to an attorney directly.
First, I'd contact the product producer and ask about branding/copyright removal. It's often not an issue with additional fees.
Second, I'd express to the client that simply removing the branding/copyright may be against the terms of service for the product and could possibly result in legal action on behalf of Company X (product owner).
If you've done the three above items... remove the branding. The onus then falls on the client to protect themselves. It's also wise to retain all communications regarding the matter.
I would always advise you from doing something which you know is not legally right. As a lawyer, I'd argue that correspondence about illegal matters is grounds to further hold a person responsible as clearly knew what he was doing was the wrong thing to do. The same way a soldier in Iraq isn't allowed to fall back on the excuse they murdered unarmed civilians because their commander told them to do it. If they know it's an unlawful order, they will be held accountable.
Now on to my own personal experience, I have been asked to do this by an employer (distinction between client) on several occasions. All of these times I refused and explained why it was wrong and why I wouldn't do it. The first request was asking me to copy the entire code of a competitor's website and rebrand it as our own. For one, I explained you can't even see the bulk of their code that makes their site work, but even just the visual appearance is copyrighted material. They also asked on another occasion for me to use a logo for another company and turn it into a logo for one of their companies. Their reasoning, "the owner company is a Mexican company and they don't have copyright laws."
As you can see, these situations are different than yours, however, you have no idea if the terms of the license state the copyright must remain intact. Until you know this information, you could be fully within the rights the company purchased, or you may be doing the wrong thing. Don't be that guy.