Pedantry time: We have tags for both theft and robbery. Neither have wiki descriptions at time of writing. What is the difference between them? Or is the difference negligible enough that they should be aliased?
Personally, my gut feeling is that a robbery involves coercion through violence -- "Your money or your life," etc. -- while a theft is simply taking something, often without the target even knowing. I don't know if other people feel the same, though.