Which characters are allowed in an org-id

[michaelwood]

Trying to write a validator for org-ids. What characters are valid?

[Bjwebb]

I don't think we've really decided this. IATI says they should match the regex [^\/\&\|\?]+, so that they can be used in URLs http://reference.iatistandard.org/203/activity-standard/iati-activities/iati-activity/reporting-org/