The problem isn’t transfers to, its transfers off the servers, because the bots basically go to empty servers, fill up a level 1 alts, then push all the consumes to higher population servers. So if you blocked characters below 60 from transferring with herbs/mines/etc and made everything bound it would solve most of the farming problem at least on smaller servers, where they get used a feeder server for mankirk/whitemane.
There is zero need to do anything about GDKP servers, as you simply wont find one, and if did, it wouldn’t matter.