I didn't have amateurs reading their work at sessions in mind. I meant the pros. Here is the poet who got the biggest audiences of all time, reading his most famous work.

Yevtushenko reads Babi Yar

It's a professionally made film. It would have been easy to cut away from the sheets and obscure his eye movements reading from them. But nobody thought it mattered.

Some more you might have heard of:

Allen Ginsberg

Charles Bukowski

Tom Leonard

Alice Walker

Audre Lorde

Seamus Heaney

Jean Binta Breeze

John Cooper Clarke

Andrei Codrescu

John Hegley

George Szirtes

Jacques Prevert

Simon Armitage

Attila the Stockbroker

Patti Smith (reading prose by Oscar Wilde, but she performs it like one of her own poems).

For every poet I could think of who might have made it to Internet video, what I found was them reading from paper (apart from one video of Jean Binta Breeze where she is acting in character as The Wife of Bath in Brixton Market). And in most cases what they were reading from was a published copy of their own book - not a privately marked up copy, they were using exactly what their readers had access to.

I have at times had a fair amount of poetry memorized. But performing it from memory would NOT have been what the author intended.

One of the most memorable live poetry performances I've seen was when six New Zealand poets (led by Ian Wedde, I think) read the index to Freud's "The Interpretation of Dreams" aloud in unison as a piece of found surrealism. Take a look. I can't imagine anybody memorizing that.