Newps wrote:

Greg Esres wrote:

That's not always the case. And to make matters worse, the pilot
has no way of knowing without direct knowledge.

When would that not be the case? And if it were the case, the pilot
must certainly know. If you don't hear the words "radar contact"
followed by a heading, then you're not being vectored.

No. A heading issued with a takeoff clearance is a vector.

If the term "for radar vectors" has not been stated, the prudent pilot
should ask, "Is that heading assignment for radar vectors?"