Currently I can't find a way to stop non-trusted players activating tripwires on your island. It would be nice if a way to enable/disable their usage by non-trusted players was added to the /island settings menu (the same way as pressure-plates). This would allow players more control over their island's redstone builds.
I've never really thought of this before but it would be useful for some people if this was added into island /settings, support.