I just had the coolant expansion tank strap recall service performed. Took about an hour.
The issue is the coolant expansion tank is made from two pieces that, over time, can separate. The strap is metal and wraps around the edge seal of the tank, holding it together to reduce the risk of separation.
The technician first tried to attach the strap while the expansion tank was inside the engine compartment. That didn't work -- the strap is just long enough to reach and he couldn't get the ends to meet for the connecting screw. He drained the tank, removed it from the car, and completed the strap attachment on the bench. Went very quickly.
For others getting this done, I would recommend that you tell the technician to remove the tank and do it on the bench from the start. The whole job will probably take no more than 30 minutes -- probably 20.