Can mostly confirm this. No warnings whatsoever, but they simply don't air controversial shit at all. They maintained this policy down here even during CN's heyday in the late 90s and early 2000s, I remember those times very well.
For instance, they never aired the infamous Buffalo Gals episode of Cow & Chicken. And a good portion of those Looney Tunes, Tom & Jerry and other old-school shorts that dealt with racial stereotypes, like blackface? Big nope on those too.
The same thing happened with Nickelodeon. Ren & Stimpy was considered so juicy and crass, it only aired on the MTV cartoon block together with stuff like Beavis and Butt-head. The usual cuts on Rocko's Modern Life were also there in certain bits.