Comments: The circumstances of this concert (including whether it even happened) are among the most puzzling in U2's history. Multiple sources, including publications for radio listings from February and March 1981, advertise a date of 14 March. The second publication was included in the US I Will Follow single as a poster, which can be viewed here thanks to U2Songs. This date is also printed in the book U2 Live. Over the years, sources have listed the venue as The Olde Globe Theatre. However that location was destroyed by fire in 1978 and did not reopen until 1982.

An advert in the Daily Times-Advocate on the 5 March (which bills the group as U-2) and a second in the same newspaper from the 12 March both mention the band performing at San Diego State University's Backdoor Cafe on 13 March, as found by U2Tours; this is also where the information on the support act comes from. However events at the Backdoor would usually be advertised in the student newspaper The Daily Aztec, and editions from that time contain no mention of any U2 concert at that venue. Moreover, in a 2005 newspaper article the Backdoor's talent booker of the early '80s stated he passed on booking U2 as they requested a fee of $1000 USD and he "didn't think more than five people would come."

A recording purported to be from this concert exists and is where the setlist comes from, but if anything it only muddles the details even further. At one point Bono mentions having been there (i.e. San Diego) before, however this was U2's first concert in the state of California let alone in San Diego. So we have two ads promoting a U2 concert in the city on 14 March, two further ads printed later on with a date of 13 March at a venue that denies they were ever booked to play there, and Bono's comments during the recording purported to be from this event suggest that he either forgot it was their first time in the city or the recording itself is actually mislabelled and comes from a different as-yet unidentified Boy Tour concert. Although we are fairly sure a concert in San Diego did take place, as a result of all of this we are unsure of when it was, where it was, and possibly even what was played.

What we believe to have happened is this: several dates previously on the tour had a late change of date or venue; one such example took place in France just three months earlier and another caused the cancellation of what would have been U2's North American debut. It is likely that a date of 14 March was originally scheduled, but after the initial radio promotions the concert had to be rescheduled to a day earlier for unknown reasons. Whoever was in charge of booking locations was confident enough to list the Backdoor in ads but this fell through during negotiations over the fee. A last minute change to a currently unidentified venue that was available on the 13th was made as a result.

As of 2022 we list a date of 13 March and the venue as the Backdoor as that is the information in the ad closest to the scheduled date of performance.