WORLDGUARD-2977 - Reported by Luuk.Jacobs

http://www.youtube.com/watch?v=TT5KILxwIeM

It's also worth noting that all trees are capable of growing into towns, but only dark oak trees can actually destroy blocks other than air. This is a problem for people who have valuables or trade signs located near the edge of their town. Though the chances are low of this ever being abused, it's a problem nonetheless.
(saplings were placed against the region, on the edge)

This is a bug report from a user on ECC, this only happens with dark oak, perhaps because acacia and dark oak use a different block ID? (LOG_2/162 instead of LOG/17)

(note, we refer to most regions as "towns" on ECC)

Full bug report from user:

Brief Description: Dark Oak tree saplings can be grown in a way that overrides any block that isn't LWC'd, including trade signs and blocks within towns you aren't a member of.

Instructions: It's slightly complicated, so I made a video on it. I recommend pausing it to read the captions, but most of them should stay on screen long enough anyway.
http://www.youtube.com/watch?v=TT5KILxwIeM

How many times did you recreate this bug?: 3 out of 3 times. However, the frequency of the tree actually growing towards the town is much lower. You merely have to keep growing it until it works, but it always will eventually.

Result: Breaking blocks I'm not supposed to be able to break, such as those within regions I'm not apart of or trade signs that aren't mine.

Expected Result: The tree to check the blocks and not grow into them.

Evidence: The video above.

Additional Information: This has been private messaged to you to prevent abuse by the community until it can be fixed. Luckily, this is a widely unknown bug at this moment in time, but I wish not to spread word of it's existence in fear the wrong people may hear about it and abuse it.
It's also worth noting that all trees are capable of growing into towns, but only dark oak trees can actually destroy blocks other than air. This is a problem for people who have valuables or trade signs located near the edge of their town. Though the chances are low of this ever being abused, it's a problem nonetheless.