Use ruuvi as presence beacon

I have an office space with multiple tags for temperature monitoring. The area is covered by Ruuvi gateways that push the data into the Ruuvi cloud.
I would like to be able to use some tag to verify presence. It seems a bit cumbersome to me to poll the sensor data to achieve that. Is it possible to create an alert on tags entering range and being lost?

Thanks for the advice!

There is an existing RSSI (signal strength) alert that can be triggered when RSSI reaches specific threshold. We also added a new alert type called Cloud Connection, which can be configured to trigger an alert if sensor has not been seen in specific time. This alert type is available in Pro (and higher) subscription packages.

Check out the subscription packages at https://cloud.ruuvi.com

That sounds like an efficient way to go. Can alerts invoke a webhook?

Not on the Cloud service currently but a new Ruuvi Gateway firmware 1.14 is rolling out to beta literally today which will give you some possible options: Ruuvi Gateway firmware updates - #2 by Alexey