@grid7 Hi Sean, I created a short demo for using a temporary dummy user. You can clone it from here to see the details: Dummy User Test
Basically I am using the current time in a custom formula to create a new dummy email address.
I had to put the sign up action on a button. For some reason I did not get it to work with an action on the screen itself.
When the user decides to sign up the dummy email and password will be updated keeping all related data.
The user collection has a IsNamedUser property that is set to true with sign up.