Yes, the drip tip screws off, but if you look carefully you'll see that the plastic top of the inner tube contacts the outer tank surface at the top. This plastic fits snugly against the outer tank and the only way to get juice into it is to slide a needle between the plastic insert and the tank.
It is very easy to fill, as in the tip just unscrews, but you have to fill it with a needle, which is not hard at all - I just don't like carrying needles and syringes around.