I think @ianoc tracked that down to the fact that you guys are running these inside scalding jobs that validate all the tabs in the flow.

If we do something similar in summingbird, that sounds fine, but I think if we merge this, pipeFactoryExact will be broken for anyone using it inside summingbird. Can we add this:

https://github.com/twitter/scalding/blob/develop/scalding-core/src/main/scala/com/twitter/scalding/Job.scala#L235

here:
https://github.com/twitter/summingbird/blob/develop/summingbird-scalding/src/main/scala/com/twitter/summingbird/scalding/ScaldingPlatform.scala#L607