CS PhD, used to be a professor, have worked at several industry research labs since.

> this practice is quite bad mannered, unusual, and heavily frowned upon,

Yes, it is.

Maybe you missed my point?

The fact that is "quite bad mannered, unusual, and heavily frowned upon" does not stop it from happening, and it is common for all high profile inventions and discoveries.

This does not disqualify the person doing the scooping, history remembers them as having the credit, and quietly forgets the person who was scooped.