It's not really recommended, but I do not recommended things all the time. I don't usually charge overnight though, as I have enough batteries to not need to do so. If you can get that going, it is probably slightly safer than charging overnight if you can.
I don't like the idea of my house catching fire.... Oh wait, it already did, my husband managed to get a lit cigarette under the house. He (and the fire dept) were able to extinguish it, but let me tell you, living as a person who had to flit from rental home to hotel and whatever, until we were able to get back in the house a year later... Not so fun. Nor is UNPACKING all of our stuff (still working on it, LOL) so I tend to be more cautious about things these days. It would have been EVEN WORSE if all our stuff went up in flames. Homeowners insurance is a mysterious tangle that takes FOREVER to sort out.
Anna