I have seen that oil containers are lined up outside Los Angeles but have no more insight into it. Will June production be less?
June 2020 futures have been trading since 2018. Small oil producers, unlike Saudi and Russia, hedge their oil by selling calls or buying puts or a combination of them.
Where does this end? Just transfer that negative premium to oil producers to NOT send the oil. However, this won't happen, as negative prices tend to happen on the last two days of the front month. Unless we see negative for July futures right now (in April), oil producers just follow their contracts.
What it meant was that future sellers had to pay for buyers to accept those futures. There was enough capacity to take that oil.