There's an option in the arcade software called "auto prune". As Al_B says it keeps it competitive. The current highscore stays for 30 days only. So far I've had more support for it than against it so for now it stays.
I think it's great. Gives more people a chance of geting a high score rather than just one person who gets the high score on a game they know well and then fecks off never to play again. To say nothing of the fact I suddenly went from 6 high scores to 11 overnight last week without having played for a couple of days :]]
I agree with admin,I have a few at the top,but would like to play more one off competitions with others,more fun.
its ok to delete high scores makes the game fun but what would be better i think is if admin would send you a message saying it has been deleted