There is a field on Account called IsExcludedFromRealign which determines that if Account is excluded from Territory Assignment or not. I am having an issue where some of my accounts are not assigned to a territory even though they match the criteria. (More about this on this link: Why Account Assignment Rules removes Account from Territory?) However, I am unable to query this field in Workbench or Dataloader. How do I get the data of this field?
Your query would look something like this:
select id, Name, IsExcludedFromRealign from account where IsExcludedFromRealign = true/false
I've tested it and it should work, of course choose true or false.
Also, here's a pic of my run:
I can reproduce your problem with the Data Loader, Workbench, and SoqlExplorer. It doesn't seem like this is available via API. Either that or you (and I) should log a case with SFDC.