Originally Posted by
chaadster
If I were worried about it, I'd just stick a Torx head bolt in there (unless I needed a quick release, in which case a Save Your Seat Lock would be the ticket:
http://www.saveyourseatlock.com/buy.html).
If I were really worried about it, Pitlocks.
Zefal makes a locking seat post quick release that is a lot more low profile than that one. I've never seen it online from vendors in the states, but stumbled across it when ordering some parts from Australia. IIRC it was about 15 bucks. Somebody must stock it though.