I think that basjoos was the first with the caulk and that he used a razor blade to split the caulk so that he could open panels ect. I'm sure he'll chime in. I've been using scotch tape. Works like a champ and if you need to open something just peel and stick more on when your done.
If you want the car to actually look decent, you could use bondo, sand it down, and re-paint. Then it won't look as if it were tacked on. Use an exacto knife to cut a small enough gap to open the hood/doors/ect, while preventing any significant disturbance to attached airflow.