I have following setup:

1. 2 jobs:
   1. main job is configured to listed for SVN commit hook and build when commit happens
   2. deploy job is triggered by this plugin in non-blocking mode and does only a deployment (don't listen for SVN stuff)
2. Email-ext setup on both jobs to e-mail in case of failure

In case if failure of main job I get the e-mail, because actual e-mail address is retrieved from user, who did SVN commit, which triggered the build.

However even though I've set "Include/passthrough Upstream SVN Revisons" I don't get e-mail. I guess this option doesn't pass the e-mail addresses from upstream job to be used in case of failure by Email-ext plugin.