I definitely approve of cross-training; I'd note that the most advanced DBA written maintenance, backup, etc. scripts I've seen are extremely simple by any experienced developer's standards, and I often encounter "that's too complex" resistance from DBA's on requirements thatare both few and fairly simple for any real development project.
Likewise, developers should cross-train on the database admin side, and everyone in IT should know more about the business, if only to be able to ask better questions about requests coming from the business, which can lead to providing better service.
P.S. at large companies with regulatory boundaries, I haven't seen personal relationships bend rules and regulations (I'm sure it happens, but it can in some industries generate major fines, firings, investigations, and/or lawsuits), but I have seen them bend the "process" - not the rule, certainly not the regulation, but instead of sending an official request and getting a denial back 4-8 days later with the reason and then you try again, you can ask a question or explain the situation first, and have a much better chance of sending an actionable (and accurate) request. Perhaps you even get a faster response when it's important and you explain that in a sidebar.