DHCP client is required on CHR installations since most of cloud services provide only access through IP address and you do not have direct access to console.
In order to make it happen, CHR checks if there is an IP address on ether1 interface or on bridge if ether1 is in it. If there is no IP address or DHCP client, then one is created automatically.
If client is disabled, then still new one will be created in case it was disabled by accident.
If there is a static IP address on ether1 (or bridge) new DHCP client will not be added.