When I write a package, I usually call external functions using pkg::fct() just to make it very clear and explicit where the function is coming from. I'm aware of the small overhead, but can usually ignore it.
On the other hand I like it when all external functions appear in the roxygen tags to give an overview of what is used in the function.
Is there a way to automatically add all functions called via pkg::fct() to @importFrom? And is that a good idea after all?