Taking Requests (Moonwalking With Einstein)

I recently finished reading a great book on the art of memorizing called Moonwalking With Einstein.  It was a deep dive into the training that is necessary to be a national memory champion.  Yes, that is an actual contest.  The book, unfortunately, had no actionable information to help me get better at memorizing songs.  
I have trouble remembering words to songs.  Even songs that I’ve written, I continue to struggle with until I’ve played them 63,284 times.  I feel that it’s unprofessional to use a cheat sheet but I get nervous without a crutch.  
I’ve been working on memorizing songs and I have become more confident with the number of songs that I know very well. I am playing a show that will require more upbeat covers than my normal set.  It’s a one-hour set. It shouldn’t be a big deal.  I think I have it down. I’m not overly confident but I should be able to get through an hour.  
It just occurred to me, that someone might request a song that is not on my list. If there is a song they want to hear, I should play it.  I don’t want to disappoint anyone. I might be back to using a crutch.  There are so many great songs out there and I can’t memorize them all.