Let me make it quite clear - we have no evidence that anyone is cheating to find bases. So many bases have been griefed in such a short time, that it is no surprise that cheating is suggested.
The general feeling having investigated this is that most bases are found by flying the roof for portals and other signs of activity and then checking out the local overworld area. None the less we will remain vigilant in searching out any use of unfair methods.
For those of you new to building on raid grief server, here are some tips.
Other methods of legitimately finding bases, include infiltration of groups, by befriending or buying coords. Not everyone plays nice, I'm afraid. Make sure the person you invite to your base is really who they say they are.
Higher entity numbers, fully grown kelp in oceans, and any other signs of player activity are all clues a base may be nearby.
Build far out and avoid basing on diagonals and NSWE axis as players follow these. Also keep away from the border. Its a place to visit. Build far out in the nether ( beyond 25k ) or base far out in the end. These are much safer. I have seen some fantastic bases far out in the end, and yes it is possible to get villagers there.
As someone who has lost bases in the past, I fully sympathize with those who have been griefed, but this is something I've thought about and it simply wont work to have safe areas for builders. Some exceptional bases have been protected in the past but it only causes jealousy and resentment amongst other players.
As there is no evidence that anyone has been cheating other than the number of bases affected, it is not acceptable to make baseless accusations in chat or in this forum.
Crafty has kindly extended the world border and this should make it possible to build reasonably safely, if you take careful precautions.
Enjoy the server and the extra room for exploration, have fun and I'll see you on there.