2) Do you REALLY think someone checks people's credentials and the race results from races they have said they completed on their entry forms? That would take a very keen, and enthusiastic organiser with a lot of spare time on his/her hands indeed!

I doubt that his would ever be done. However spot checks wouldn't take too long on the internet. I think the main aim is to leave you in no doubt as to the difficulty of the race that you are entering. If you lied it would also give the organizer some comeback in any ensuing litigation. God forbid.
The rest of your problems seam to have been well answered by other forumites, I hope you see their very valid points of view.