When webbing is on passages other guilds can look at the passage and remove web from it.
Once removed they can no longer see it.

[Naohhi] We'll look into it, but for now, you're making giant errors pop up all over the place on this side. :p
[Naohhi] That means.. please stop.
You have some tiny scratches to the wings.
Javac exclaims, "You didn't see me!"