Not that it's much consolation, but whoever buys your house is in for a nice surprise. XD Consider paying it forward, maybe? I'm sure you can find a new house with some stuff left in the cupboard. :P My own house had a few surprises for me when I moved in. :)
I do agree, though. A warning would be appreciated to avoid this sort of thing happening accidentally.
Actually, i decided to be an evil glitch, and just spend money selling my house, then buying my old one back to clear it out, and re-buying my new one!
luckily it only cost me about 1000 currants, but basically wiped me out! Maybe a "removal service" option would be nice. Say for 500 currants, everything could be transferred to your new place for you?