I think it's kept in some kind of standby mode at low speeds then kicks in automatically when over a certain speed, when IT chooses to kick in and can take the driver by surprise, the car tries to move to the centre of the lane (or what it thinks is the lane).
Multiple times they attempted to steer me back into the oncoming vehicle because it thought I was too close to the edge. You can disable it but only for the current trip; so every time we got back in we had to go through a 2-3 minute checklist of disabling the murder settings.
LKA is practically never strong enough itself to overpower an actual driver and force the car to swerve especially if the driver had even a reasonable grip on the wheel.
If the nudge of LKA was enough to startle the driver and have them swerve then just normal road feedback into the wheel would also cause them to startle and swerve.