Trashing the HD?

Hey guys, I'm really sorry about taking up space on the site, and I promise to delete the thread (if that's possible) as soon as I have the answer, but I'm just curious:
Recently, I clicked and dragged my Macintosh HD icon around the screen, and I noticed the trash can turned into an "eject" arrow, as if I was trying to eject a disk. Afraid of what might happen, I put the HD back, but I'm curious: Does anybody know what would happen if you dragged it to the trash, but didn't empty the trash?
Please note: If you don't know the answer to this, I DO NOT encourage you to find out on your own.
Again, I appologize for asking a question that makes me look dumber than a bag of hair.

You can't eject the Macintosh HD

When you let go of the icon on the eject symble an error will pop up

"The disk "Macintosh HD" is in use and could not be ejected. Try quitting applications and try again"

Yup, so now u can try it urself!