The Soviet robot rovers are mentioned in the article
In fact Lunakhod 1, the first successful robot rover on the Moon placed
there in 1970, is a potential unknown threat, as they lost contact with
it and do not know precisely where it is or if its laser reflectors are open.
Details are here:
http://www.zarya.info/Diaries/Luna/Luna17.php
We are safe with Lunakhod 3, however, as sadly it sits in a museum on Earth.