If something requests for the drive to open, I'm pretty sure it's just going to open. Most drives are designed to cease motion when they come up against resistance anyway, so you should be ok if it ever gets triggered by mistake.
Na that's not what the problem is. The problem is that some programs such as CloneCD, some other burning programs and I guess even the joke programs will open the cd rom drawer without confirmation from the user. This is extremely annoying if your case has a door as the cd rom will try to force the door open.
On my case (Coolermaster Wavemaster) if the DVD Burner drawer is told to open via software the drive opens instantly, puts pressure against the door, forces the door to open which then swings open, bounces back and hits the open cd rom drive. Not very pleasant I can assure you.
So far I haven't found any solution to this problem, apart from leaving the door open if you're using a program that you know can open the cd rom. Perhaps there is a way to disable windows from listening to the signal but I haven't been able to find anything.