I was willing to pay extra for a climate controled storage locker. And I would check out the lay of the land to make sure that if the area was flooded that water seepage wouldn't be a problem. And of course if you miss enough payments on your unit the contents can be sold.

I'd also make darn sure that no one was around when I was filling the unit - so onlookers couldn't see that there were portable and easily pawned valuables inside.