EXISTINGNAME_01 sounds like a programming option. Do you mean it is possible to set the default way?
I have a train interior. The link block seat_first_class is using a fine adjusted leather material at the main scene file. If I would choose “automatically rename”, than the seat block wouldn’t be connected to the leather material anymore. A new leather_2 would be created and connected to the seat block, right? I don’t know an easy way to reconnect the material of the seat block to the well adjusted leather material of the assembly file. So,the connection is broken. If I would save the main assembly file and open the next time, than the connection to the leather material can’t be bring back anymore.
The full story is - the project contains three different types of first class seats, all linked blocks. Per “automatical rename …” I would lost the connection to the adjusted leather material. Dangerous option.
At Vray for Rhino the option “keep the original …” is the default option. It works very well since years.