Great argument, but there are several useful features that punkbuster has, which are invaluable to maintaining the integrity of the gaming experience; in this case, making sure that knuckleheads don't modify the game/mod, in particular, the .tweak files I would think. It also ensures that there are layers of administration available on the servers. What you're calling for (and I don't think you realize it) is anarchy in a gaming experience which is already ruthless and at times frustratingly harsh. Here's the list of functions performed by punkbuster, grabbed from Wikipedia:
PunkBuster - Wikipedia, the free encyclopedia
Real-time scanning of memory, a feature also prominent in many programs, by placing a PunkBuster Client on players' computers
searching for known hacks/cheats using a built-in database.
Throttled two-tiered background auto-update system using multiple Internet Master Servers to provide end-user security ensuring that
no false or corrupted updates can be installed on players' computers.
Frequent status reports (encrypted) are sent to the PunkBuster Server by all players. When necessary, the PunkBuster Server raises a violation which (depending upon settings) will cause the offending player to be removed from the game and all other players to be informed of the violation.
PunkBuster Admins can also manually remove players from the game for a specified number of minutes or permanently ban if desired.
PunkBuster Servers can optionally be configured to randomly check player settings
looking for known exploits of the game engine.
PunkBuster Servers can be configured to instruct clients to
calculate partial MD5 hashes of files inside the game installation directory. The results are compared against a set configuration and differences logged, and optionally, the client removed from the server.
PunkBuster Admins can request actual screenshot samples from specific players and/or can configure the PB Server to randomly grab screenshot samples from players during gameplay. However, it is possible for a game hack to block screenshots (producing a black screenshot) or remove all visual features of a hack (cleaning the screenshot) to remain undetected, leaving the effectiveness of this feature diminished.
An optional "bad name" facility is provided so that PunkBuster Admins can
prevent players from using offensive player names containing unwanted profanity or racial slurs.
Search functions are provided for PunkBuster Admins who wish to search player's keybindings and scripts for anything that may be known to exploit the game.
The PunkBuster Player Power facility can be configured to
allow players to self-administer game servers when the Server Administrator is not present entirely without the need for passwords, in which the players can call votes to have a player removed from the server for a certain amount of time.
PunkBuster Servers have an optional built-in mini HTTP web server interface that allows the game server to be remotely administered via a web browser from anywhere over the Internet.
PunkBuster Admins can stream their server logs in real time to another location.
PunkBuster has initiated Punkbuster Hardware Bans,
that bans hardware components upon detection of cheats that disrupt or circumvent PunkBuster's normal operation. These bans mean permanently banning players whose HD id matches the blacklist at Evenbalance. The cheater will have to buy new hardware to be able to play again.