Bootleg oil in the industry is called "hot oil". In the old days it happened a lot, especially in the East Texas Field ("The Black Giant" - "The Last Boom" highly recommended reading) to get around pro-ration quotas.
It is uniformly strictly prosecuted, typically involves moving oil by vac truck 40 - 80 bbls at a time, almost always during daylight when it would arouse less suspicion.
If it is one producer stealing from another it's a capital offense. The only theft I know of since 2004 was 16 bbl from a lease way out in the woods on a rainy night. That's about what you can put in two "totes" in the back of a one ton truck.