There is no likely scenario that would allow a 1000 times cme.
The one possiblity is an impact by a large object like a rogue jupiter that might cause this event and then, the odds of the cme aimed at earth is maybe one in a thousand if the 1000 times cme occurred.
I didn't say anything about a "likely scenario".
Fact is a CME 1000 times larger than anything we know about could happen. No?
It’s like the chances of you getting on a plane and crashing and dying are extremely remote...But it happens.