The Jethro Tull Concert was cancel because Ian Anderson had a cold, or a sore throat. It was cancelled last minute because they weren't sure if Ian Anderson was well enough or not to perform that night. That day, April 6, 1971, WNEW-FM, A NYC radio station kept saying that the show was ON, right up until we left N.J. by bus to get to the Fillmore East. The locally somewhat famous WNEW-FM DJ, Scott Muni kept saying that the show was on, so we hopped the bus and took the A train downtown to the Fillmore East, where they told us that the show was cancelled, and we had two or three options. One - get a refund, Two - see that night show which was Humble Pie, Cactus, Edgar Winter's White Trash and Tin House, a 3 piece bluesy band, formed from 3 members of EWWT, Three...I Think...See that night's show and buy tickets for the rescheduled Jethro Tull show. I believe that we took Option Three. The ONLY puzzling thing is this...If I'm remembering correctly, how did they get tickets printed so damn fast for a rescheduled show - ?
It could have been option Two, and we could have bought tickets for the rescheduled Jethro Tull show at the Garden State Plaza in Paramus, NJ, from the Red Barn clothing store, a ticket distributor for the Fillmore East.

I've always felt that this slap-dash put together show served as a practice run for Humble Pie's album Performance Rockin' the Fillmore, recorded on May 28–29, 1971.