So on rumbles, we always turn off PIS. This means that Wally West, being a reasonably smart guy who has demonstrated competency with his powers, will steal the speed of his opponents before their neurons can fire.
We also have Bloodlust on by default, which means Superman will ruthlessly murder Professor Xavier, turning him to red mist in a microsecond. Bloodlust also means we assume characters like the Sentry, who sometimes can barely get themselves out of the fetal position, are assumed to be having a "good day" and firing on all cylinders.
CIS, on the other hand, is on by default. Character induced stupidity means the Rhino, who is supposed to be very dumb in the narrative, probably won't think to thunder clap against smaller, faster opponents.
How does CIS apply to folks that are ruthless but also arrogant enough to do really dumb things in the narrative? Vegeta is a good example. His Saiyan pride has repeatedly gotten his ass kicked by letting people power up to their strongest and such. To the point that other characters say "Damn it Vegeta what is wrong with you." Goku has similar examples, albeit without as much blow back. I'm sure you could find examples in comics of villains doing similar stuff.
How do we treat guys like that? Old school Vegeta was usually out for blood already. So does Bloodlust override his arrogance, or us that considered CIS?
Edit: I'm not sure the above applies to current Vegeta, but I think DBZ Vegeta works as an example regardless.