Which is plenty for most folks (I originally planned on installing a Level 2 charger in my garage, but found it was completely unnecessary and just charge off a standard outlet)
Sure -- I use such a setup sometimes when visiting family.
It's not ideal, however; it's 66 hours continuously to add 200 miles of range to an older S; for more efficient cars (that get 4 or 5 miles of range an hour) it's still going to be 40 hours.
Such a setup is totally untenable if you're hanging an electric cord out your window and over a sidewalk or through trees or whatever, if you can even get a parking space within extension cord range of your car...
Also, broadly -- running a random outlet at 12a continuously for 60 hours may break things in unpleasant ways.
