The invisibility option seems to turn off the AI, pretty much that.
I noticed this as well. I'm sure it's all well and good when you're just running around, but any follow or chase mission you get is broken.
I also noticed something with editing money. The first time I did it (In Havana) I was able to buy out everything in the store without any problems. I gave myself like 100,000R, and ended up with like 50,000 at the end or something. When I pulled into Nassau, the first time I went to the store, it dropped my money down to 999 after my first purchase. I could re-edit it, but every time I buy something, it drops back down to 999.