Ah! All very good points. It appears that I was pretty close to the general theory with my original post; I just assumed that it was the wolfblood that made the Wolfriders special (not too farflung of an assumption! It usually is the wolfblood that makes them special) rather than the ability to send.
In any case, I hope this explains the situation with those immortals who actually use usenames and not their soulnames like Suntop et al.