We made our 3/8" plate full pen also just to be on the safe side. I filled the groove up and backgouge the backside and filled it back up. Alot of times we end up filling the groove and putting a fillet weld up the back if full pen was not required.
I agree 100% about the detailers and checkers needing to know alittle about welding and the correct symbols to use. I was a detailer and a checker in my former life outside of the shop. I would ring up drawings when I was checking, for incorrect weld symbols, and catch flack for it. But it all stems back to the fact that they simply don't know.
I had met with a Community College here in town and they developed a course that was "Welding for Non-welders" and it taught basic principles of welding and the symbols. It was directed toward managers and engineers that wanted to learn more about what they are asking the shop to do.
John Wright