No, activation based licenses are not locked to a single Host ID (for example, MAC address, Disk serial number, Flex-ID) but are locked to a given machine based on the composite machine identifiers which include the Host-IDs.
An activation license uses a trusted storage area on the client or server's hard-drive to store the authorization credentials.
When the Vivado tools look for a license feature, they are allowed to run if this trusted storage area contains the proper authorization.
Because of the nature of activation licensing, it is not possible to lock an activation license to a single Flex-ID dongle in order to transfer the license from machine to machine.
An activation license can be returned from one machine and activated on another machine at any time.
If you require the use of a dongle to move back and forth between machines, you will need have your license entitlements converted to Certificate based licenses.
To request a license change from Activation to certificate based licensing, open a technical support case with the following information.
For information on Certificate and Activation licensing, see the Xilinx Licensing FAQ: