Fully contained doesn't mean the fire is over. It means that a line has been scratched around the fire, or that workers have been around the perimeter. It does not mean controlled, or settled/closed out. This is a public misperception.
Very often after a burn has been brought under control, it will be re-ignited in firing operations to burn out a control area. Simply because you don't see smoke or fire, or other aircraft, doesn't mean that the fire operation is over.
How do you know that air ops are over?
I've worked fires for which NOTAMs remained active for almost six months and others which lasted only hours.
It was only a few years ago that nine jumpers were killed in a flashover in a burned area that was "contained" and no longer active. It had been completely burned over and they were hiking through to another part of the fire when it reburned and killed them. (Storm King Mountain). Never assume that simply because you can't see it, the danger doesn't exist for you, or others.
I was advised of an aircraft a few days ago just prior to my drop. The air attack had a brief visual on an airplane putting himself where he certainly didn't belong, and I got word just prior to making a tough drop in a rough place. One extra distraction I didn't need, and at a time I didn't need it. If the TFR is there, definately observe the limitations given. If you see smoke or ops in progress, stay well clear even if there is no restriction. The life you save might be your own, and mine, too.