Saying it's safe to "ignore" anything that exposes information is dangerous. You might as well claim social engineering isn't real as long as the person doesn't have direct access to the thing you want.
But also stuff like RAG: usually support agents have access to all internal support kbase material. Including stuff you don't want to leak verbatim. And there's other things to consider too like your agent being used to run other people's prompts. Not a data loss issue but could be a financial issue.
But yes I do agree that for the tools' security the agent shouldn't be considered as part of the security model. Any protections there are nice to have but shouldn't be relied upon.
This is exactly what I mean; if you give your agent access to some knowledge base through RAG; you should assume that this knowledge is now public information. If you don't want it to leak, design your agent so that it doesn't have access to it.