Are transactions rolled back during failure?

While observing #470 and #471, it became apparent that transactions may not be honored as expected. In the attached .gif, two plates are added for prepare shotgun libraries. The first plate is added with the correct primer plates and the name "FOO", while the second one has the primer plates juggled and uses the name "BAR". An exception occurs, as described in #471 because the primer plates for "BAR" are incorrect. The .gif then shows an attempt to redo prepare shotgun libraries but this time only with the first plate, using the name "FOO", with the correct primers. We observe the duplicate name violation in #470. Despite the failure, the name "FOO" and possibly other state has been committed to the database.