It seems pretty cool. Although the "player touch" event is annoying, and kind of pointless. You could always make a common event with a conditional branch with a specific button to be pressed that would bring up the thievery option.
edit: actually, I'm gonna mess around with this a bit and see what I can do.
edit2: well, I messed with it a bit. I got the common event to work, only downside is, is that you have to press enter AND the button at the same time for the thievery menu to show up, but I guess it also offers something cool. I also changed the "banker" name to "victim, because it's a common event.
If you don't want to attempt to rob that person, just put whatever else you want to happen under the 'Else' part of the conditional branch. (Not of the common event, of course.) I also made two different common event. One that will alert the guards, and one that just makes the person yell in surprise, and it also deletes the event to give the illusion the person ran. Oh, and the buttons to bring up the thievery menu are ENTER and the W key. Oh, and ignore the Parallel Process on the common event, I don't know why I did that. It can be set to 'None'.
I'll play with it a bit more. I attached it to the bottom of this post.
edit3: I updated it again, I added a new map showing how it could easily be used in a town.
edit4: Updated yet again, but I added an 'Intro' map that explains how to use the system. Sorry if it seems like I'm stealing your idea, but I'm trying to help you improve it. Take a look at what I've done and see what you think. Again, I've attached the new updated version to the bottom of this post. Also, please post of any bugs or errors you find, because I'm sure there are some.