Those of us in geological fields totally disagree with you. If you start a small earthquake in San Andreas, say up in the northwestern section, you can trigger a full-length chain reaction that culminates in unleashing the big one which will rip all the way through Mexico. What is worse is that the earthquake will get stronger as it propagates along the fault line. What you call the big one in the northwest section where it all began is thousands of times weaker than what gets felt further down the fault.
It might not ever hit. Crustal rocks can permanently store tremendous amounts of energy as stress; if the stress is changing, the fault might only move enough to release some small delta of the total stored stress. But: grease the system and you might release a lot more, and all at once.
It's very hard to predict what will happen, either naturally or human-triggered. IMO this is a good argument to not rush it. Every day that passes gives us more time to understand and prepare.