THERE IS NO CHARGE FOR A ONE DAY OVERSTAY AND IT HAS NOT BEEN CONSIDERED SERIOUS IN ANY WAY. I HAVE HAD AN IO AT THE AIRPORT MAKE LIGHT OF IT SAYING WITH A SMILE SOMETHING LIKE WHAT A NAUGHTY BOY YOU ARE. I HAVE DONE IT AT LEAST THREE TIMES OVER THE LAST 17 YEARS WITHOUT ANY REPERCUSSIONS SINCE APPLYING FOR OR EXTENDING VISAS.
I'm speaking from experience over 17 years. I've done it at least three times entering by land and air many times since with various visas and had no problems. Also the arseholes at my local immigration office thumb through my nearly full passport over and over again trying to find something to find fault with but they never can because I am totally legit.
I have done this many times over 17yrs to stay an extra day before my return flight. There is no fine for one day and you do not get a red stamp. Just a small square blue stamp with a squiggle and never had any consequences.