The Desperate Loner: Why isn't Guerrilla advertising used more?

There's an interesting interview over at Ad-land about the use of guerilla advertising (streetvertising, assvertising, etc). I found this excerpt about staying on strategy to be most insightful.

db: You know, that bit about using or inventing new channels is interesting, but sometimes it seems as if that is the only thing you do when you "do guerrilla". Nicorette did these really nice enamel signs in the London Underground ten odd years ago, where they were placed right underneath the non smoking signs. Nicorette's sign read: "it's times like these you need Nicorette" (or words to that effect). There, the new channel is perfect for the target group but sometimes you see new media invented just for invention's its sake. Could you name a "right" channel and a "wrong" channel, and how does that happen?

Fredrik: Yes, often you see that people mess it up just by throwing out some fun happening at a town square without thinking. The key word is relevance. Then you'll meet the target group where it is so incredibly spot on. If for example, you are going to create advertising in the toilet it's an advantage if the company and the message has something to do with shit. And all that. SMS advertising is something that I personally don't believe in much.
Advertising on the back of parking tickets isn't always good either, although right now were actually doing something where an extremely relevant message would fit nicely on a ticket. Those "home made" notes that are stuck everywhere and are difficult to remove aren't that much fun. I was never a big fan of "wild posters" either. What I do like are things like our "price tag" for hyresgästsföreningen, as it was distributed via the members magazine and they themselves put the tags up on their doors to engage other people in their building. There's been an inflation in post-it notes and I don't want to use that again no matter how relevant it might be.