Heard a neat thing today on the radio

Was flying VFR Twin Oaks to Tacoma Narrows, approach brought me in to the ILS to 17 and wouldn't give me a visual. On about three mile final I had been switched over to tower, given landing approval, then a Cessna called in for taxi instructions (?). Tower answered back "taxi instructions not available from this unit, 121.8 (which is ground frequency)". Now I've had this happen in real life when I was training in San Diego, had the radios set up to swap ground and tower but called tower for taxi instructions, they told me just about the same thing... interesting indeed, and what a neat thing to include in the programming. What'll these guys think of next?Zane