Yeah... A lot of people get really careless with PaRappa's level 2.
Whenever I use it, I at least expect people to use their supers if they have one. I just do a little feint before actually killing them, to see if I can get them to waste one.
My favourite way of killing off PaRappas though is to have a skateboard collision.
And I've killed a Big Daddy who was using his level 2 by using Sir Dan's level one JUST as he was using his air charge move at me before. That felt awesome.