The truth is in the APIs (Score 1)

I'm no lawyer, but I have to believe that the underlying technology has to come to play here.

Gmail provides two APIs for managing mail in Gmail:

1) IMAP - clearly you can create, read, update, delete emails through IMAP. LimitNone would be silly to sue Google for creating an IMAP client for migration purposes.

2) The email migration API. In true Google fashion, this is a REST API that only supports one way posting of mail to Google. It is very single purpose.

gMove used neither of these. It instead, used non-supported, non-documented protocols that the navtive Gmail interface uses to talk to the server.

Sure, gMove may have been a clever implementation, but a robust product it was not. If they were charging customers for a product built on an ever changing, non-documented API, that's the risk they understood. Hell, their customers should be suing them for false advertising.