Sure you can!
And this werks, too!
You put a paperclip(preferrably a couple of them) between the target's door and the doorpost, and wait for him to leave the house.
Now, for the next part...
When he closes the door, he won't notice theclip, and "lock" the door as usual...Just that the door won't close completely, and he won't actually lock it!
Now, seeing as the lock jammed against the doorpost, he will examine the door, and notice the paperclip!
When he bends to take it, you run behind him,and into the door(Which he opened so he could retrieve the clip, duh...>_>), without him noticing.
WHAM!
Insta house rob!