Ewan MacColl often used to introduce a song by saying, "this is a request". But these 'requests' were often so well programmed in to his and Peggy Seeger's performance that I often had my suspicions. Perhaps he was ensuring that he didn't get too many 'real' requests for stuff that he was sick of singing (?)

Having said that the last time I saw him perform, I requested a song during the interval and he did actually sing it for me in the second half.