I realize there are WL/GM tools that reduce the getting-stuck problems somewhat - if you are traveling with one or they are available to come to you - but it would seem a good building practice to, when creating an area that will have a portion of walkable but inaccessible space (such as an area behind a wall with no exit), include a climb to get a character out of it. I was thinking about this when considering a tileset problem that would likely lag a character into a huge amount of walkable/inaccessible space and thought, "we could just put jumps there..." I think I mentioned it before, but it was shortly before the inclusion of the WL jump stuff. They're not always around though, any more than GMs are.
I realize that "trapped" problems are less common than "stuck" problems, but the former can be alleviated completely by including a means to get out of such locations. For a true stuck situation, the best you can hope for is a DM/WL jump, a campfire prayer, or a `makesafe.