a0d929ca_WSRP_v2_0_Specification__Statement_text
[#] CS204 [Section] 7.5 [Statement text] 
If the optional Lifetime field from getPortletsLifetime is not returned for a particular Portlet, then scheduled destruction is not in use for this Portlet and the Consumer MUST use the destroyPortlets operation to destroy the Portlet.
WSRP v2.0 Specification
Statement text