I'm not an RN yet (4 more months!) but I work at the Children's NICU and have had clinical at Riverside's NICU (as well as two graduates
I have never seen a traveller at Children's NICU as an RN. I know we have a few traveller RTs in the NICU, but never an RN. I think because the orientation period is so long, they don't want to invest the time in travellers? Or the fact that there are always people who want the positions and want to stay in them? (at least that's their intention)
We use the float team heavily when we're understaffed, or pull from PICU.
Riverside, I've also never seen travellers, they have a very strong contingent staff base to pull from when they need extra staff. But it's another highly desireable hospital to work at, and I doubt they have any shortage of applicants when they are looking for new staff.
We also have a LOT of very good nursing schools in the area that are constantly churning out new nurses.