I wouldn't call it being an idiot if I were you.

I have used many compacts without their covers on. Every time I perform a repair or adjust the screen, I start it up like that. I always will power up without the cover on after I fix something just in case I forgot to reconnect a cable (I have a tendency to forget the four-pronged CRT cable that attaches to the analog board) or if something I put in is DOA and I didn't know it (this happened to me once with RAM, which is why I always do it like this now).

Once all is well I put the case back on and insert the four (sometimes five) screws.

Speaking of opening cases, did anyone else see the Mac Cracker on eBay today?