Or if you have a doubles player who does not show, or injures herself in warm up, and you do not have a sub, you would default that spot. You cannot rearrange names that have been listed on the original card. You can imagine the confusion and juggling that would occur if this were allowed. A savvy captain who has scouted your team would take a look at your line up and rearrange her players to best match up with yours, giving her team a definite advantage. Rules call for a 5 minute warm up, which starts then.
Many teams take longer, depending on how tight court time is.
A visiting team hoping for more warm up time, but not sure if they will have it on the home team courts should, whenever possible, warm up ahead of time at another location. This is hard if there is a long travel time. Some sections of USTA have adopted this format for Sectional and District championships. NorCal has not. We will continue to use traditional scoring for all local, district and sectional play in 1999.