This is a rather moot point. All the LI battery fires I've every read about are from cheap imports. If you're using Bosch/Shimano etc I don't think this is a particular issue. That said, I do unplug the charger once battery is charged (unless it's still not charged & past my bed time!)
https://www.london-fire.gov.uk/incidents/2023/january/maisonette-fire-stratford/
Just a reminder to not leave your battery charging overnight/unattended etc and so on.