I thought that TSAFS with the /EnableGW=yes was supposed to "protect"
the groupwise files that were open?

We use the TSAFS with that switch but I'm seeing odd things like this on
Veritas NetBackup 6.0 MP5:

SERVER6: ERR - can't open file: PO6:PO6/ofuser/USERIEI.DB (SMS:
FFFDFFF5: (TSAFS.NLM 6.51.4 266) This data set is in use and cannot be
accessed at this time.)