This reminds me of the time a visiting HS baseball coach took a fungo bat out to hit to his outfielders before the bottom of the first inning. Fortunately, there is a specific rule against that, which he didn't believe.
He did believe I'd eject him, though, if he didn't take the bat back to the dugout.
I think Bob's citation is good enough. Beyond that, it's a technical for not following the directives of an official.