Difference is green does not permit going off-path. They're the safe option. No UPS difference.
I tend to use white off-road most of the time, and green for:
- Pausing carts while rebuilding or correcting a layout.
- A line of greens acts as a barrier that will catch stray carts.
- Anywhere I absolutely need to be reminded that there's a path and not to build over it.
- Whenever layouts are dense and error-prone, like around stops.
