No “Creative” mode builds. Town members may not use any materials created by admin commands, or request admins to build/clear any areas using their commands. Basically, builds should only be created as if Creative mode does not exist. Exceptions: You can use tools/armor regardless of how you got it, and if some /kit command is available to all players that is fine also.
Presumption of Community ownership. If you want to store personal items, or create a building that you want no one to ever modify, you must place easily visible Signs stating this clearly, like “Bob's Vault do not touch” or “Statue by Alice, do not modify”. For any build without such a sign, you can assume that any member of the town may modify any build. This also includes using resources left in unmarked chests, as long as they are used for the purpose of building the town.
note: For private storage containers, you should just use LWC to lock them, making the Sign redundant.
Do not kill, steal, or destroy. You may not PVP any town member inside the town borders without their consent. You may not take resources left by another player for usage outside of the town, without their permission. You may not totally remove or ruin another players' build without permission from them or the town owner – but you may add to any build, including making moderate changes to improve a build in any way.