Not actually @finnian , someone could access your account and just stalk on you until you had some significant value in your account and steal you.
However if he were to make a transaction it would be logged so you would know however it would be too late...
If you think your account might be compromised reset your password and maybe talk to steemit support so they can check if someone logged from other Ip than yours
Also storing your password on your home computer might not be the best place use a usb stick or a memory card... and always have a paper backup hidden