Quoted from cyberslunk:
compared to pros I would be considered laughably bad. Should I still enter for the heck of it or is this frowned upon?
If you think about it, you are either going to have laughing, or frowning, but not both. But I honestly don't see either happening. If anything you should laugh at yourself if you do well, or poorly. Most importantly, have fun, and don't care about how you do or what other people think.
Most people who really care about how they are doing in a tournament/ league will be worrying about being neck and neck with the person scoring a little better or worse than themselves. Or they are going to be thinking about...what if i nudged the game a little more or little less/ would I have done better or worse.
That way you can't lose. This can be applied outside of pinball as well.