I had commented on this on a previous posting, under the impression this was only being done in Japan. But Tesla has started offering this here as well - a 30 minute charge is free, or a battery swap is $60-80 but only takes a minute and some change.
FYI, they also achieved the highest NHSTA safety rating of any car ever rated. And in the test to see how much pressure the roof of the vehicle can take before it gets crushed, it broke the testing equipment!
Hopefully some of these high-end goodies will trickle down to us common folk!