Another reason you MIGHT want your detachable dive computer in your carry on:
Those suckers are expencive, and we have had experience with our dive gear being tampered with in airports. We're lucky it was only a stolen compass (they were trying to get the puck computer out of the console).
Almost all my family's gear has come off Ebay, if you're careful there are some great deals to be had, like my mother's brand new Mares reg with computer worth around $2500 for $500. I also got a new Henderson wetsuit last year for around $60. I could go on, but I won't.