Romas, thanks for share your experience. We've had the same problem too.
In this case, the system would handle it in the 'Merge user interface'; I mean, when you will merge two accounts the 'Merge user interface' will ask you wich will be the good account(GA) and then it will take the role of the GA by default. However, we could add an option that let the user to choose wich of the roles will be setted.
I hope that answer your questions.
