It would be nice if there was a command such as /membership that would display all the towns that you were a member of.
There is a command already implemented into Worldguard which would allow you to do this. /rg list .me Regions (towns) you own or co-mayor off would show up with a + in front of them, regions (towns) you're a member of show up with a - in front of them. More infomation on their wiki. http://wiki.sk89q.com/wiki/WorldGuard/Regions/Commands#List Currently no permission is granted for this commands but it would be well worth adding! and thanks for the suggestion otherwise I wouldn't have looking into this.
I personally wouldn't need this, but it sounds like something that would be convenient for others. So +1