a0d929ca_WSRP_v2_0_Specification__Statement_text
[#] CS201 [Section] 5.11.2 [Statement text] 
Portlets/Producers handling this event SHOULD be aware that idempotency concerns related to the Consumer's processing of the request it received could limit how it processes items returned from the processing of this event.
WSRP v2.0 Specification
Statement text