SVNKit checks out to infinity by default if unknown is given as the
depth to checkout. If you're using as-it-is you probably don't want the
whole source tree, so change as-it-is to set the depth to files for
checkout and unknown for updates.
Not sure how flexible to be here some people might really want immediates or empty instead of files. But files is probably close enough isn't it. There could be an extra setting for this but I don't think that necessary.