i've advised many a woman that there are a few sins they commit on their men, that are basically unforgivable . they might ACT like they did, but they will never do it, and you've broken trust...
basicaly it boils down to "if you don't respect them, at least respect their stuff, and never, EVER take it, move it, or gods forbid, THROW IT OUT. ***NEVER*** (voice of doom) or you WILL regret it"
a buddy of mine had a super snoopy girl, and he was saving cash money for a special trip/vacation/ring. he kept the money in the back of an old radio his dad gave him. girl decides that the radio has to go, and one day without telling him, just gave it to a friend. a week or two goes by. he goes to put some money in. radio is gone. she acts all coy, like "what radio"... he is PISSED. eventually tells her that he had $$$$ in their for their special trip/etc because he couldn't trust her to not snoop and find it elsewhere, spend it, or demand new shoes or something. well, they goto their friend, and ask for the radio back. money is gone. friend denies everything. now, they've lost a friend, and shortly later, the girl lost her guy.
that said, someone's girl better not do anything permanently bad if she did take the BK2 (like engrave it with hearts and shit)
hope you get *a* BK2 back, if not the one she pretended to steal (it probably was college students, looking for money for drugs, asshats ;>)