Legally speaking, you also want to be careful about your dependencies and their licenses, a company that's afraid to get sued usually goes to quite some lengths to ensure they play this stuff safe. A lot of smaller companies and startups don't know or don't care.
From a professional ethics perspective, personally, I don't want to put my clients in that position unless they consciously decide they want that. They hire professionals not just to get work done they fully understand, but to a large part to have someone who tells them what they don't know.
I'm still sorting all this stuff out personally. I like LLM's when I work in an area I know well. But vibing in areas of technology that I don't know well just feels weird.
In the LLM case, I think it’s more of an open question whether the LLM output is republishing the copyrighted content without notice, or simply providing access to copyrighted content. I think the former would put the LLM provider in hot water, while the latter would put the user in hot water.