A blue bicycle card box has a BLUE back and a RED front.
If you align the deck so the RED FRONT side is shown when pulling the RED BACK deck out, and the BLUE BACK side is shown when pulling the BLUE BACKS out, you're laughing.
The audience don't CARE what colour the box is, usually
Another alternative I've used is to have the deck rubber-banded and placed in a small brown manilla envelope, which is sealed.
Works a treat, and looks totally tamper proof
Bear in mind, I didn't do this because I thought the deck from box was iffy, I did it cos it fitted my routine better!