From Pierre,

The way the checkout step is mandatory in order to get the revision log is a bit constraining, in our position, our builder does the checkout, hence it is useless to
have Quickbuild to do it first, but if we skip the checkout setp, we have no modification log, nor is Quickbuild able to go and check if there was any modifications and
fetch the usernames in the VCS, I think that those two actions should maybe be independant, we could be able to check for modifications without having to actually
checkout sources, I thought the last revision was in the DB and checked against the current revision by doing svn info.