Major Description
If our users let HBase manage ZK, they probably won't bother combing through hbase-default.xml to figure that they need to set hbase.zookeeper.property.dataDir to something else than /tmp. It probably happened to deinspanjer in prod today and that's a show stopper.
The fix would be, at least, to improve the Getting Started documentation to include that configuration in the "Fully-Distributed Operation" section.