Disable auto date select

Using this plugin for a client who is very busy and gets fully booked weeks in advance and as a result people are not paying attention to the dates they are booking (i know, some people are just dumb).

The reason for this is that the calendar automatically chooses the next available date/time. Would it not be better to allow the user to choose a date then check the availability then if unavailable it would say rather than skip along?

Best wishes
Mat