I've been protected on US.

I was on a LAX-PHL MR segment that left quite late, which put me in danger of missing my connection home. Given the late hour, many people would miss the final planes home for the night.

US had BPs and hotel vouchers waiting for everyone upon landing. I also got notifications of the new flight changes before I got off the plane.

However, we were also told that our current BPs were still valid if we could make our flights.

Made my flight, didn't have to use the protected segment, and I had no problems.

I think you got an agent who either didn't know how to do it, or didn't want to do it.