Registration field default value

Hi,

I am creating a website using the events plugin and I would like to know how I can make sure the registration URL/email field is not prefilled with the administrator emailaddress.

Not all events on this website will require registration so I made the field optional. I also made the changes to make sure when the field is empty the registration button is not shown.

Now I would like to have an empty field by default, instead of the prefilled administrator e-mailaddress.

Is there any way to do this in settings or in the functions.php?

Thanks in advance,
Marloes