Medicine is all about estimating risk vs. benefit. How could you possibly lump all surgeries and all patients together (for a consensus) and say the risk/benefit of anticoagulation for post-OP AFib is the same? We still have to use our heads.
Someone with massive intra-OP bleeding and ongoing anemia following a surgery which itself carries a high risk of post-op bleeding is not going to be a great candidate for therapeutic anticoagulation. Someone with low risk surgery and lots of risk factors for thromboembolism is likely to be a great candidate.
In my experience, alot of post-OP AFib results from iatrogenic volume overload (i.e. post of CHF). Fix the volume and you usually fix the Fib.