I understand and somewhat agree, however, if I was ever in a situation where I felt that LE had stopped searching and I felt that searching could possibly find my lost family member, I would try to organize private search parties but try to do it the right way by using experienced search groups like Texas Equosearch , and the like.
There are so many things that have to be taken into consideration like getting permission from land owners if private land for example. Safety is a must too and things like that. Liability is an issue too if someone gets hurt, they could try to sue the search organizers.
So, I would most definitely try to do it the right way. As far as disrupting evidence, that would be easily handled by just making sure people are instructed to not touch anything if something is found. Something has to be found first before it can be disrupted, so I sure would not let that stop me from trying to find my missing family member. Its like someone saying...dont go in the woods and find your missing family member because you may disrupt something and then we cant prosecute them. Well, IMO, thats too bad, because I darn sure am going in those woods to find my family member since nobody has found them yet.
I suppose I am just the type that could not sit around and do nothing if I found out that nobody else is doing anything.
A case like this is tough because there really is not a focused area that is better than another place, so in this particular instance, I am not sure where I would even begin to focus. This might be the example where I too may be forced to wait for something else to surface before I could focus further. We get a sense of how hard some of these cases must be for LE.
At a minimum, i would probably walk her path home many times back and forth. That would be the minimum i would do. It never hurts to retrace even if its been checked once.