I noticed a few other posts on here relating to the Frogger episode and theorizing that the game had a "hard drive", etc.
Hard drives aren't used in arcade machines. Battery-backed RAM is often used because it is much cheaper and more reliable. However Frogger had no such backup--the scores die when you pull the plug.
The REAL inconsistancy in this episode is that Frogger doesn't take initials! When you get the high score it is placed next to a "1st". Second place is "2nd", etc. I noticed this because it is something that has always bothered me when I play Frogger.