SummaryWhen dealing with Adaptive Response, there is no direct way to determine how much of a quota they have used. However, there is a way to make estimates based on monitoring.
OverviewWhen a user belongs to an adaptive response policy, which allows for a maximum amount of data to be used (quota) before placing the user inside of an object that will shape, slow or otherwise manipulate their traffic, it would be useful to be able to determine how much of their quota they have used in the policy's period. While there is no specific way to do this on an explicit 'how much of the quota as a specific user used' basis, there are ways to be able to get an estimation of the amount of data they have used in general over a time period.
WorkaroundIf Active Directory Integration is enabled and users are showing up through their AD credentials, looking at the users monitoring panel (Monitor > Users) will show the top 50 users in an organization and various metrics, including how much data they have used over the monitoring period. By changing the monitoring range to a period of time that is close to the adaptive response policy, you will be able to get a picture as to how much data has been used by a user so far and manually figure out how much of the quota that is. For example, if the policy is set so that the quota resets weekly, the monitoring period can be said to 'current week' and the resulting metrics will show how much data the user has consumed since the start of the week in MB. If you have a daily policy, you can look at the 'current day'.
If you do not have AD Integration enabled, then the same type of monitoring can be doing through the host monitoring panel (Monitor > Hosts). This will give you an overview of all hosts and their type of traffic. If you are looking for a specific host, you can filter the graph by IP address. It will show a list of the top internal talkers and internal listeners, and will show the Total Volume of traffic. By changing the monitoring range in the top right corner, you can, like with user monitoring, choose a period appropriate for your adaptive response policy to see how much Total Volume they have used during the period.