It is always preferable to talk to someone before turning them in. In an ideal world, this is great and this site would not be needed except for updating people on the drought conditions.
Typically, unfortunatly, talking to your neighbor causes issues, threats and other hostile behaviour. Talk to a clerk in Stripes about their watering, and you get a blank look.
But we are in a crisis, so, this is a reminder that we have a serious situation, and we have to conserve.