Everyone ever hear of insurance not approving even though all pre-reqs met?

Anyone ever hear if insurance will deny a surgery when all the pre-requisites they laid out were met?  I am just curious if this ever happens -- my paperwork is being submitted in a day or two.  I don't want to get my hopes up TOOOOOOOO high if there's a chance they can deny it anyway.

I have heard of it, but usually your doctors office can work with you and the insurance company to resolve any issues.  

They cannot legally refuse to pay for WLS if you meet all the requirements in your policy.  Sometimes doctors' offices fail to submit all the necessary paperwork or something like that, in which case they don't know you've met all the requirements and then they deny the request.  But then you just make sure you submit everything they need and they approve it.  They cannot just arbitrarily deny it, though.

Some insurances consider WLS cosmetic and will not pay for it, I'm a state employee Nd my insurance didn't cover it for the weight loss  they covered it for my acid reflux, it's the same surgery just under a different name 

Thanks everyone.  I believe mine does cover it if you meet the qualifications (BMI over 40, etc).  I'm just a worrier by nature :)