I've stopped incorporating these "what was I doing earlier" questions in my RCs some time ago, because I wanted my RCs to be more frequent yet shorter, but I'll start doing this memory check again.
Although, once in a non-lucid dream I needed to find a backpack or something like that, which I knew I had earlier, and I tried to remember, in the dream, what have I done with it earlier. This resulted in my brain making up a false memory on the spot of where I placed the object, even though that never actually happened. Isn't it likely that our minds will create false memories like this during a dream and RCing with this memory check?