Which isn't really a significant risk if the store owner doesn't hang around. I mean, someone could also hold me at gunpoint and take me to the bank, which isn't a great idea. If I wanted to emulate that, I could put my wallet in a safe deposit box.
Then they kidnap your family so you go to the bank yourself and withdraw the bitcoins.
I think you're failing a bit in criminal imagination, which is probably not a bad thing altogether.
How is that any worse security than keeping money in a bank account?
That's my point. Bitcoin doesn't solve any sort of problem that isn't already solved via traditional fiat currencies.
They could do the same thing if I had USD in the bank.
s/bitcoins/online banking username and password/
How does one pull money out of an online banking account using only the credentials?
By logging in and initiating a transfer?
You could store the BTC on an address that requires multiple signatures.