Since there's no rule that says discs count as part of the robot for certain purposes, there's no good reason to believe that this is an exception. (Do discs count as they're being ejected? Do they count when they're in the goals?) It should be 100% permissible.
And as for next year, if FIRST wanted to kill all the interesting, unexpected strategies, they might as well simplify their effort and just make the next game robotic
dressage. I trust it won't come to that.