Keep coming across many servers where people just get kicked instantly, or blocked on joining public server.
Some give daft reasons (blockers) like your name cannot contain letters, or 'no room for you sir' (on a server 8/30)
Obviously, this is either groups or clans, looting up on servers and blocking or kicking everyone else.

The list is quite large, so have only included a few as example

JOIN = BYE BYE Warburtons magic hat
108.61.116.14 : 2302
Game servers.com

Dayz
185.16.87.55
Fragnet

Twitch PVP allowed
185.16.84.60 : 2402
Fragnet

All told, since update has been pushed to stable, the increase in public servers doing this has increased drastically.
Public is public, and these people/admins are abusing the system