Discovered this when I gave an irrigation auditor access to my Iro yesterday. I shared access from the App (not the website) and saw that the auditor had full access to the system forever. When sharing access through the website we can choose the permissions level and access time. Since I'm more likely to have my phone with me than the computer it would be great if these options could be included in the app as well.
On a different note, he said being able to use the app saved him so much time that he was able to be more thorough than the 90minute block usually allows.