I had my reserved car given to someone else with a similar name a few months ago, and it was booked using a membership program (albeit Hertz #1 Club Gold, rather than Avis Preferred) - they even charged my credit card for the car someone else had taken! And my surname is not that common (although not totally uncommon). It was also at my home location, where a number of the staff know me reasonably well. It was a hassle getting it all sorted. Did eventually get a free day rental out of it though.

Note that this was in Australia, not the US, but human error can happen anywhere!