I like Janitch's suggestion but realize it might be a lot of work. For now I'm glad SDBs are locked because it means I can give much freer access to my home than it would be able to otherwise.
I love having storage options that are only able to be accessed by me. It's comforting to know that my gigantic hoard of crap is safe no matter who i let into my home or give a key.
I would like to be able to see how much of each item is in my friend's SDBs by mousing over, however. It's fun seeing how much people hoard. I just don't want to be able to take it.
I like that some things aren't accessible by keyholders. If you want friends to have some things that you would normally keep in an SDB, build a cabinet and put some of the stuff in there. That way, it still looks neat, but you still have some items protected in the SDBs, to include valuable things such as rare items and one time gifts.
I think personally the only way to combat this problem is to have different types of keys as obviously people will always feel differently to what key holders can and can't do. Maybe have 2 - 3 different keys? Each one would give you a different type of control on things you can do in someone elses house.