Strategy 3 : 

Engaging the local bars and shops in the locality to take ownership of nearby public spot which is endangered and also it can take note of the people visiting bars. 

A creative initiative of bar owners and other commercials to make a great difference. 

Also, a platform for government body handling 311 data, can come with an app to bring together people concerned who would want to help the city combat such problems. 

Also, people can anomalously, register spots on a map on this app. 

This would involve a high cost but it would be suggested as it would tackle other issues as well. 

Precedent:

 http://promisetracker.org/