When looking into Zope's internal representation of permissions and so forth, I found something strange... Suppose, for example, I have checked 'Anonymous' for 'View' on a particular object, a new attribute called ' _View_Permission' is created in my object. Here's the strange thing: If I leave 'Acquire' checked, _View_Permission = ['Anonymous'] If I uncheck 'Acquire', _View_Permission = ('Anonymous',) Please confirm or deny my hypothesis that the sequence data type assigned to a particular permission is the only way that Zope determines whether permissions should be acquired or not. It appears to me that the use of a list is Zope's internal representation of a checked 'Acquire Permissions' box, and the use of a tuple represents an unchecked 'Acquire Permissions' box.