In a 2 server , client are mounted using fuse mount as- client1#mount -t glusterfs server1:vol /mnt client2#mount -t glusterfs server2:vol /mnt removing server2 using remove-brick won't affect the client2 operations. but if user mounted using nfs - client2 will be affected.
nfs-mount will become inaccessible only when the system is shutdown. remove-brick don't really have the same effect as remove-brick with fuse-mount.