I'm supposing most people don't go around making every person an admin.
As you can see, both the dev team and I think that it's your responsibility that your admins behave well.
I must strongly disagree with this philosophy. A person who is a friend today, could easily be an enemy tomorrow. The conflict between administrators could be between a second and third person, neither of which are you. It is very naive to interact with humans, or program software, based on an assumption of trust.
That said, consider another scenario. A black-hat-hacker has used a man in the middle WiFi attack on your administrator's laptop at a coffee shop that has a WiFi-hotspot. Your administrator's forum password is sent via clear-text HTTP, and is caught by the hacker. Because of the forum post I am replying to, this vulnerability in your extention (or one like it in PunBB itself, if we bothered to look) is found in MetaSploit (google it!).
The hacker owns your administrator, and YOU... because you were too lazy to write a regex filter for <META NAME="KEYWORDS" CONTENT="your keywords,go here,separated by a comma,but not a space">