EDTA: Did you notice when running through the wood wearing Bella's jacket, Rosalee rubbed against the tree, but she also breathed on it, to purposely let the tracker know what they were doing?
Actually she was not breathing on the tree - she was sniffing it to check the scent.
In the books everyone makes it very clear that Bella is to be protected at all cost that she is Edwards soul mate and none of the Cullens would dare let anything happen to her and risk living with Edward for the next century.
Plus Dr. Cullen pretty much but Rose in her place and told her that Bella was family and they protect thier family.