We are building a mobile application where the user uses a mobile application to send a message to the assistant that wants his help. The user should be able to see on the sticker his position and then after entering it, it press the button to "Get Assistance". Now what we want to prevent is a user going home, open the application, then enter the position again and press the button "Get Assistance". This is going to be a multi location application and we can not put too many constraints. We need an idea that is practical.