It could be made up, I don't know for sure. Nevertheless, during the TAAB2 tour in June 2013, Albert Hall gig, when Anderson was regaling the audience with tales between songs he claimed this very thing himself. He said so in person, within my earshot, witnessed by both Mrs Bassfinger and my friend Oz, and everyone else sat there who was awake.
Whether it happened in reality is one thing. That Anderson has claimed that happened is beyond question, and I have no reason or evidence with which to doubt it.