Considering the only reason to go down pumphouse in a raft at this level is to fish and drink large quantities of beer, operator error is the 'norm'. Pumphouse at this level is the most boring, lamest run to do in a raft or kayak anyway. I will not even take a beginner down it in a kayak. But feel free to do it to your hearts content if you like it so much. Better to tell someone what could happen and if the feel like doing it anyway they are forwarned.bullshit.
you can take any sized raft down it to around 350. one short mandatory drag at below/around 250cfs. if you are getting stuck beyond that then it's "user error".