restricting slots

hi, trying out your plugin (which is great) prior to probable purchase of Pro.
I am going to be using it as a bowling green booking item but it appears that there is no restrictive measures that i can implement.
I know you can limit the minimum and maximum number of slots a customer can select while booking but the customer can then refresh the page and book another slot again. Is there a way that i can restrict bookings to 1 or 2 per email address at any given time? Does the pro version have more restrictive options?

Thanks

Robbie