I've got a WordPress booking theme where I've embedded a GravityForm questionnaire on a booking page, and I'm using the GravityForms User Registration plugin which takes the user name and email address in the form and creates a WordPress user with it, which is handy.
The problem though is that even though the user is created, the plugin doesn't automatically log them in. So even though I've customized the GravityForms submit button to submit both the GravityForm and the booking request form, the submission of the booking request is blocked by a login modal (because the user wasn't logged into the new account that was just created).
So customization #1 is to make it so that the user account that was just created is used to submit the booking request, without needing the user to log in separately.
The next related issue is that this plugin doesn't detect whether the user is currently logged in. So if the user attempts to create a second booking using the same email address on the form, then the plugin attempts to create the user all over again, which causes an error that says a user with that email address already exists.
So customization #2 is to have the plugin simply check to see if the user is logged in, and if so, bypass the registration functionality.
If this is something you'd like to handle, please mention my first name only (Tim) so that I know you read this message, and I'll be happy to answer any questions you may have.