I've noticed that more and more Li-ion tools are being made available,
but given the careful charging and handling requirements of the
batteries are these going to be dangerous for site or DIY use?

There are many examples of Li-ion batteries exploding and injuring
users. And it is recommended that these batteries are not left
unattended when charging.

As these batteries are more likely to be knocked and sustain unnoticed
damage, I wondered if they can be trusted?

dg