[wsia] [wsrp-interfaces] redirectURL field in InteractionResponse datastructure

Lines 30-34 of page 36 in the v0.3 draft spec ask what will be the
semantics of this field (introduced from the JSR168 interface). I would
suggest that the semantics be "the entity would like to show the user a
different URL". It would then be up to the Consumer whether this replaces
the current page or launches a new one (choice likely depends on the
browser in use, etc). Replacing the entity's portion of the page would seem
to be a weird thing to suggest as the URL is not likely a WSIA/WSRP entity.
If it were an entity, a single URL is not enough with the current design.

Are there use cases driving the insertion of this into the JSR168 interface
that this would not cover? Are there use cases that would not be covered by
the link the user clicked directly going to the new URL?