I've witnessed stacks of cash far in excess of that.
However, when it is done, there is usually a fair bit of armament around the cash, and the kinds of people that keep that sort of cash on hand are also not the sort you want to commit an amateur robbery against.
Doubly so in the UK. Here, the police can presume without proof (and have done so) that any cash in excess of GBP1000 is the "proceeds of crime", and the onus is then upon the owner of the cash to prove that it isn't.
Sounds like a convenient rule for law enforcement to incriminate people when they have a "hunch" about their illegal actions.
When I was 12 y.o. I had that sort of money in my bedroom (years of saving money from my paper route job, and factoring inflation). Of course, I could prove that it was mine, but it seems like the bar is somewhat low if it's set at GBP1000. It's the kind of money that you use to pay to rent a cottage for your vacations, not ludicrous drug-traffic amounts ...
But what would be the other options for a normal user? You could completely hand over your wallet to someone else, but that sort of defies the point of Bitcoin: they could log transactions, be raided by authorities, etc. You could store your wallet in a way that's physically secure (say, on a flash drive), but this just requires the hacker to insert software that waits until you try to spend some of that bitcoin. You could maintain many separate wallets on separate flash drives, so you would only lose part of your savings to this sort of attack, but that is inconvenient.
The only solution I'm coming up with would be to hand over control of your wallet to an anonymous-yet-trusted third party who's hidden behind Tor or such. The difficulty is in finding (or creating) an anonymous-yet-trusted party in the first place.
I've witnessed stacks of cash far in excess of that.
However, when it is done, there is usually a fair bit of armament around the cash, and the kinds of people that keep that sort of cash on hand are also not the sort you want to commit an amateur robbery against.