Love love love this thread - Tidy you have acted with such dignity throughout.
My prediction for the outcome of the email to Sisterzilla... Sisterzilla will agree that Gluezilla is being totally out of order and kind of suspected this, hence the email to Tidy to find out the full situation...but although she agrees with Tidy's reasons, Sisterzilla will still try to convince Tidy to help out "just this once" as maybe Gluezilla has been let down by someone else and is only acting like this because she's totally stuck and only the amazing Tidy can make things better, and then Gluezilla and Sisterzilla will promise to live Tidy forevermore.
I'm probably totally wrong but just thought I'd throw that one in there!