Bill Kreutzmann had a cabaret card based on a fake ID that said "Bill Sommers." The Dead could only play bars based on fake IDs for Kreutzmann and Bob Weir. There may have been a draft issue, too, but in any case Bill had to be identified as Bill Sommers at certain gigs. If you look at the back of the first Grateful Dead album, you will see that the band names are listed but Bill is identified as "Bill The Drummer," in order to avoid the issue. Bill also may have had the fake ID to facilitate playing in clubs with bands that preceded the Dead, when he was still in high school.

At some point, Bill turned 21 (I think around 1967 or 68), and in any case the Dead stopped playing bars that depended on cabaret cards, so it stopped mattering. Occasionally you will see a very old (pre 67) article about the Dead, and when Bill's last name is mentioned, it is usually Sommers.

corry