This seems to be random at this point.
- Had a few itineraries with no sign of it once it was released
- Then, as noted upthread, saw it in both directions of SFO-EWR-SFO -- that was a 5 day stay in NY but it appeared at the same time for both sectors
- Then no sign of it on three other itineraries, two of which have come and gone with no sign of this feature, and one of which is coming up in 10 days time
- And then this afternoon, it appeared on the outbound sector of a trip to Europe later this month, but no sign of it on the return, so clearly it can appear just for a sector rather than a reservation in its entirety