What's a good channel scanner?

Like Linden sim-wide text? That I can definitely believe, if it is/was some bit in the message and the viewer didn't check who it's coming from.

Poopmasters idea is clever. Haven't tried it out but, back to Har's OP, it's something that you could probably detect with a script without too much hassle..

No, I'm talking about the little popups you get lower right, such as to say a friend came online or went offline (and which also appears in your chat history, in blue). They can put any text there. This is a security loophole in SLProxy, taking advantage of the fact that many internals use the IM protocol. I don't know whether the same kind of trick could be used to make white chat text, but I suspect not. It's just an example of the kind of security loophole we find in SL. I doubt any serious harm can come from these blue system messages, other than flooding your client with popups and text.