If the concern is not allowing certain feats or items, then why not say so up front and trust your players not to take then rather on insisting on keeping a master copy to make sure the players don't take them? Seems that if you canlt get people to follow the house rules without policing them there are bigger issues beyond character builder functionality.
It seems like you have an impression as to the nature of the social dynamics of our group. Again, sorry, I have given an ill-impression of the nature of my motives or how our group is progressing.
The fact that we have been playing for nearly 20+ years and I have been DMing 90% of that should speak to the success of our group as a whole. We have 7 members and the game has never been stronger. Social dynamics is a massive part of that, and we wouldnt be here if we had an atmosphere of distrust as you are suggesting. A slightly rough thing to say there

, and given the effort I go to to ensure the play experience it does upset me that someone has made this implication.
I will point out a situation where I needed the control. One player had a cleric. He took a feat which gave a to-hit bonus to turn undead from some dragon magazine. While reviewing character sheets I saw it, and realized it was effected by house rule which stipulated that "everyone gets a free tiering bonus to hit which supersedes all other feats which may give a tiering bonus to hit" which included things like expertise and this feat. Under this house rules, all such feats give a flat +1.
By having these things in place I had the opportunity to spot that the player had taken a feat that fell under this ruling, and approached him to make clear before play begun (i.e. so his expectation matched what would happen during play time). Didnt change anything, he still ended up taking the feat, but it gave me as DM a chance to ensure that the player understood the impact of the house rule on his choice.
I didnt crack down, I didnt mistrust. If anything, centralizing characters sheets aided the transparency issue.