One way to solve this is use 2 Bitcoin accounts, one with most of the funds, with the private key secured in a bank safe or somewhere safe, and the other with a small amount of funds for daily use. Of course if someone is daily trading with a large amount of money then he would still have that problem but this is true for any person who deals with large amount of money on a regular basis. In this case he simply should do his tradings from an office or somewhere secure and not from home.