sk89q/WorldGuard — pull request #337 by PseudoKnight (2014-12-29 06:21:56+00:00)
Title: Add special handling for pistons in global region; Fixes WORLDGUARD-3195

I'm not sure if this is how you want to solve this problem, but I thought I'd give this issue a nudge and offer a possible solution. This approach is mostly to avoid unintended side-effects and work as seemingly intended. Getting source to contain global would also work, but it's less obvious where I should change that.