Just used the app as a user to book a meeting time (for a phone call) for a person in Melbourne, Australia - I’m in New Zealand. The youcanbookme calendar gave no indication of the time zone, but assumed it would be my time zone (as the customer making the booking) as the youcanbookme website says “automatically detects your customer’s time zones and ensures everyone sees the right times” - but turned out that my time zone (as the customer) was not picked up. There is a two hour time difference between Melbourne and New Zealand…
The timezone for the booker if automatically detected will be based off of physical location. If you are located in NZ and making a booking for someone in Melbourne you will have to manually adjust the timezone accordingly. More info here.