A standby spot means that they daycare doesn't currently have availability on the time/day that you would like to drop off your child. Parents can let the daycare know that they are interested in dropping in by booking a standby spot. When a spot opens (either because one is dropped by an enrolled child or the daycare adds availability) then that standby request can evolve into an actual booking. 

When a standby spot turns into an actual booking you will receive a notification and your credit card will be charged.