It's not in the best interest of the auto body shop to write it off. They are just as shady, and will work to keep the estimate below the threshold of writing it off. They'd rather have the work. I believe the threshold needs to be around 80%. But they can still repair it, as long as it's cheaper than paying you out for a "new" one.
I think the 50/50 guess of it being a write off is pretty good. When my Golf R was written off, the insurance company paid out my lender(VW) for what was owing and I got the remaining money sent to me from VW. This is what will happen if you have replacement coverage, at least, this is what happened in my case.