The smoker test clicks a lot of links in Sakai , often in someone what random orders. And with tools that use state a lot, these paths can lead to Null Pointer Errors (NPE). It is unlikely that these are click paths our users will travel down. Sometimes the UI even recovers from the NPE and puts something up.
But we might as well fix these rare NPEs so future NPEs (i.e. perhaps a regression) jump out while running a future smoker test.