Interesting - I've got a Creative 12x DVD with Infra control, and it occasionally does exactly this. Generally it only opens/closes during the boot process, so I tend to ignore it.
I've only noticed this happening since I "upgraded" the PC to Windows ME. It doesn't happen to the Sony CD-Writer in the same machine, on the same IDE channel.
I think the DVD drive itself is fantastic, but I have noticed "glitches" in other Creative Labs products, eg the Live audio card tends to emit pops and crackles under Windows 2000, ME and XP, but not under 9.x.
If it wasn't that their products work superbly, and are very competitively priced, I would have gone to another manufacturer long ago.