I'll only ever leave a ball in the trap once.
I'm launching number two into the stratosphere. Some of the longest, most majestic shots I ever hit come out of the greenside bunker on the second effort..
One of the more freeing things I ever learned about golf was the bit in LSW about how good or bad (I guess depending on your view) Tour Players are from bunkers. I can get out of a bunker and onto the green most of the time, and now it isn't something I really worry about practicing; both because of lack of availability of practice bunkers and also the lack of the need. The quality of my approach shots has also improved and keeps me out of them enough of the time, too. And most of my "didn't get down in three from the bunker" instances are three-putting from places I probably shouldn't three-putt from too often, which means the bunker shot wasn't the culprit.
Yeah, it's definitely highly dependent on the situation. Based on my limited experience with how penalty areas are marked near cart paths, it's very rare to see the relief area be between the cart path and the penalty area. That's why I was skeptical but also hedged in my post.
In any event, this is really an easy situation in competition. Have them play 2 balls and take some pictures of the area. Let the committee sort it out afterwards. That's easier than arguing about it and have that hanging over your head.