You introducing a system that imposes a form of taint does nothing to prevent theft but does make using Bitcoin a hassle for those who are innocent.
Therefore I do not support this and will vigorously reject any movement towards this initiative and any like it.
A tainting system could be used to deanonymize all bitcoin owner. Anybody could claim that bitcoins from an address were stolen from him and now all tainted bitcoin owner would need to authorize themselves and reveal all their transactions to the police otherwise their bitcoins would be blocked. That would lead to subsequent malicious accusations and the authorities would feel legitimized to seize the half of the bitcoin supply worldwide. Finally bitcoin would crash.