Cacher_Chick
Test, Don't Guess!
Pushing in the pipe might remove excess cement, but if the cement is properly applied to both surfaces, it is never completely removed.
The reason they recommend twisting the fitting into place when/as it bottoms out is to help distribute the cement, which ensures that this is not an issue.
The reason they recommend twisting the fitting into place when/as it bottoms out is to help distribute the cement, which ensures that this is not an issue.