#1 - July 31, 2010, 3:50 a.m.
Actually, Dreor, the Paid Character Transfer service is intended to be used by people who want to transfer between realms. Population level is virtually irrelevant, the only time it really matters if is the population is rather high and we feel that transfers to the realm should be halted.
Please note that this service is entirely optional and was introduced to allow players who wanted to transfer realms the ability to do so for a specific price.
On occasion a realm's average population may exceed a level that we would like and in those cases we may offer Free Character Moves from a high population realm to a low population realm. Such transfer options are usually announced on the General Discussion forum. You may also check the following link.
https://www.worldofwarcraft.com/account/character-move-eligible-realms.html