Walling off building entrances and TC to ruin a base is considered griefing. So is blocking them with a turret or other non-twig barrier. Base takeovers are not allowed.
Raiders may take TC and place doors or other protection during online raids, but these must be taken away immediately after the raid ends (disconnecting or doing something else). If this is not done, it will be considered griefing.
(If raiders placed walls to protect themself against counters you can ask the admin to remove them but never wall-in the TC)
The easiest way to figure out if you are griefing is to ask yourself the question, “Am I doing this for a good reason, or just to be an asshole?”
Also, as part of the no griefing rule, workbenches can only be picked up by the base owners.
Exceptions to the griefing rule:
Players who claim a monument or quarry are NOT protected by the griefing rule.
You are allowed to take it over or wipe it.
If you are not sure a base is part of such a claim, ask the admin before taking action.
A triangle foundation with a built-in TC does not count as a base and is not protected by the griefing rule. Raid bases are also not protected by the griefing rule.
It has to be a legit base.
If any doubt if the base is legit, contact the admin !!!!