[Rivet] Question About Rivet

[Li Jinmian]

Dear All,
I am a graduate students in China and I am start to learning the Rivet.

While I am doing the standard rivet analysis,just as recommend:
          makefifo hepmc.fifo
          agile-runmc Pythia6:426p12 --beam=LHC:7000 -n 2000 -o hepmc.fifo &
          rivet -a MC_GENERIC hepmc.fifo 
          rivet-mkhtml Rivet.aida
I can get the some plots.

My question is:
During the MC simulation, which part of the process do the detector simulation?

If the detector simulation is not have been done, why the result can be trusted?

Appreciate for you kindness help.
Best wishes!
Jinmian li