This isn't a small, disorganized cult we're talking about. I haven't needed to learn about Compounds or Polygamy yet, but I've spent quite a lot of time learning everything I can in hopes of figuring out why the law lays so low here.
It's thread drift, and I apologize for that.

I have decided that our sheriff dept guys were intimidated/scared/unsure..and although they're supposed to be able to ignore those things, I can understand taking the "wait and see" approach in hopes of never having to be involved.

We don't have a Compound.
We have a School for Troubled Teens.

Mormons have Generational Memory, excellent PR skills and a talent for screaming "Persecution!" when they're caught breaking laws.
Doesn't anybody wonder WHY they keep such excellent geneology records?

I think the practical way for the Law to handle the Texas Compound would be to let the children and moms live there for a while and set it up like a women's shelter with outside staff to rehab/acclimatize the ones that want to break away. Taking them away and spreading them apart won't give them their minds and let them learn to use them.
A set-up like that would probably cost less, be more effective, create less of a stir and most importantly, it would let the 'innocents' be in an area they're familiar with. That Compound is their Home. The Believers have been put in a position where they will lose their chance at Heaven and there are very few people in the group who would be capable of living happily on the outside without a lot of help getting their feet found. They have learned to be completely dependent and fiercely protective. Some of them probably don't want to be 'rescued' and a lot of them won't have any concept of what being rescued would mean..just that it would be scary and wrong (according to their teachings)

I imagine the county law in Texas is in over their head..and had no clue how to handle the situation. They were probably just hoping nothing would happen to make them have to Do Something.
What was there to do?   Rage into the compound and end up punished for religious persecution?
Those cops are just people, not super-wise superhumans...

I don't want to pull the thread, but here are a couple links to another story for anybody that might be interested in broader information on the type of things these folks know how to get away with.

http://www.isaccorp.org/thayerlearningcenter.asp
http://www.closethayerlearningcenter.com/