From 10 Top Tips for Booking a Wedding and Party Band: What You Need To Know by Em Peasgood, Bandleader
It is very important that your band can provide you with a list of up to date references from previous clients. Some bands will even be able to offer contact details so you can talk to a previous client on the telephone.
A good bandleader will want you to feel confident that their band references are genuine. Good references ease your mind and take the pressure of trying to see a band live.