If I took things seriously, the ratio of my meaningful posts to a single liner posts ("please use the *code* UBB tag when posting code") would approach zero over time. New people come to JR all the time, and the threads are full of unformatted code. What I suggest is a "code detection" functionality, when a post is submitted. There would be some challenge for the "auto detect" to determine where the code starts and ends in the post, but it's certainly not impossible. Once the bounds are determined, the portion of the post deemed as code would be wrapped up by the UBB code automatically.
Interesting idea. Perhaps worth contemplating as an enhancement after we get a new system up and running, having attended to other more basic functionality. (Yet another thing I wouldn't want to attach to UBB.) I'd suggest that (unless it has really good AI) it shouldn't just automatically slap code tags around "suspected code", but should instead say something like "You post appears to include Java code which has not been formatted with [ code ] tags. Do you with to: (1) Edit your post (2) Submit now as is". Something like that.