Caching roles in a cookie

1)
 a) I assume roles are cached ( by setting Roles.CacheRolesInCookie ) only for current user?
b) Besides Roles.GetRolesForUser(_currentUser), are there any other methods that will read role information for current user from role cookie and thus won't have to connect to the data base?


2)
a) I assume that normally role cookie gets updated only when current user is added or removed from the role(s) or when the cookie expires?
 
b)  
Because role names can be cached apart from the data source, it is possible that changes to role management at the data source would not be reflected in the cached values. In this case, the user must close and re-open their browser to clear the cached cookie value.
How exactly could role cookie get cached apart from the data source?
 
3) If the number of ...