Considering that plumbing is being designed to be used multiple times in rapid succession, I don't think that this is something that can just be "lived with". The consequences are too severe to just live with small leaks in the hopes that they don't become too big leaks.
And considering the durations of missions envisioned for StarShip, small leaks might be bad enough to cause a RUD after an extended time when engine restart is required after a long coast phase, or perhaps on lunar liftoff.
So, even small leaks would require routine inspections and repairs before reuse, even though they did not destroy the vehicle on the previous flight. And that would be a challenge for the turn around time that SpaceX is designing for.
Frankly, considering that we have been successfully using liquid hydrogen 2nd stages for decades, I would expect that liquid methane would be less challenging to keep inside the systems.