Okay so I've seen puri_puri put the map glitch to good use on the staircases in his speedruns and I had to mess around with this myself. I tried this in the Ghost Hall Building and it's really usefull there. I was even able to break into Yuanda Zhu's room with this!

This works on pretty much all of the staircases and lots of fun and exploration can be had with this.
I've tried this in various spots and I did manage to get to the other side of the locked doors that are used by Ryo and Ren during the handcuffs segment. But unfortunately Ryo will just go through it like regular and will be back on the hallway. Of course this is extremely usefull in the Yellow Head Building. Stay tuned for that one.

http://youtu.be/aQSH1DEnb6Y

While on the quest to find Ren at Lucky Plaza, I did the Map Glitch and found Ren as shown below.

http://i.imgur.com/kivgNFb.png

The mechanics to start a conversation with him are enabled. However, when you press the A button to talk to him, Ryo goes like this: "Excuse me..." and then "Oh well...". Then all of the Conversation buttons are disabled when you try to talk to Ren.