Why are you so frightend by BD+? BD+ can not stop your pc from working or something like that. BD+ also can not revoke your drive only AACS can. The only thing Peer said yesterday BD+ can load somthing but I think it is unrealistic because they can not say that a BD is played back on a pc so I think they cannot put a trojan on there and spy your private documents and send them if your pc has internet connection to Sony...
They can and - I'm sorry to scare you - they will. They will not use BD+ to actually phone home to Sony with your personal data, because that is plain illegal (though BD+ would have the potential, shouldn't this be enough to make you boycott that crap?).
The thought behind allowing BD+ to run native code is to let "standard" BD+ determine whether you are using (potentially) compromised equipment and fix that right away without being tied to the limitations of BD+ itself.
This can be a lot of stuff like auto-updating your drive's FW or removing patches that were made to your favorite player (hardware or software).
It could also be shutting down your PC for fun, whatever.
And it is highly probable that at some point that BD+ will mistakenly detect an "evil crack" where there is none and send your system or drive directly to the junkyard.
Whether or not these things are actually going to cause this trouble is not really the point though. By supporting Blu-Ray you are effectively allowing a company to lay their hands on your personal belongings without you even knowing when and how they misuse (to some point they will) this questionable privilege.
And on top of that: you're doing this without much pressure, after all there is a much more friendly format available.
These things always happen in small steps. Today you get to opt into the BD+ scenario, you shrug and accept. Next thing will be, that you agree to phone Sony headquarters each time you want permission to watch your movie ("...and have you been a good boy too?..."). And someday someone asks you why you do such stupid things and you'll answer: "why? it's always been like that".