Cigarette lighter / power outlets

Does anyone know why the cigarette lighter and additional power outlets only work the the key is in the ignition? Sometimes when I'm travelling I need to charge my phone overnight.
Thanks.

Are you asking how to modify this situation or for speculation on Toyota's philosophy?

The obvious answer to the philosophical question is that this prevents a short or high drain load from completely draining the battery and leaving you stranded out in the middle of somewhere.

Well, how to modify if possible. Sorry, and I should have also mentioned that it's a 99.

I would take the most accessible outlet (cigarette lighter, I guess) and find an appropriate fuse (one that is on when the ignition is on with a significant amp rating) and wire the power of the lighter to the fuse contact that is down circuit of the fuse so that the lighter circuit is fused.

For smaller current use, any wire that provides voltage when the key is off will be sufficient. However, since it is unknown what current will be drawn in the future, I would make sure the fuse is pretty much the same as that which fuse the cigarette lighter in the first place.

Great. Thanks a lot.

Check my corrections.