Alas, Russian Olive can be an invasive pest.
Here in Alberta on the prairie regions it's now a "Noxious Weed" and in the Parkland regions it's no longer recommended.
The problem occurs in the coulee country: The seeds float. So they drop in fall, and then with the spring runoff do a mass migration downstream. In many stream valleys they are taking over the poplar, and the biodiversity is dropping like a rock.
This problem would likely be common to the 'basin and range' part of the American south west. -- basically anywhere that gets under 18 inches of rain a year, or more accurately any place dry
enough that there is bare ground between plants.
RO doesn't seem to compete well with grass when young, so if you are in a climate regime that favours sod grasses it shouldn't be a problem.
Sea Buckthorn (same family, different genus) is also problematic, but has received weed status yet.