Uhh not exactly. If they pick other server than Balmung, some RPs might want to stay on Balmung due to friendships they made. Which is why it would be best to stick with the same server~
Being a RPer myself, it would be very hard for me to decide to either stay on Balmung or move to the new official RP server. Many of my friends are not RPs and they prolly not wish to change the server. The concern around this matter is not something no needing to worry about actually.