When using PubNub in a server application on Heroku or Google App Engine (perhaps other hosted environments), it could cause the Daily Active Devices metric (DADs) to be higher than expected. When publishing messages in these hosted environments, the IP address may change with each publish. 

To get an accurate device count and ensure proper behavior with respect to Presence features, create a UUID and set it on the PubNub instance and reuse that UUID for each subsequent publish and request.