I photoread with great success on the train, I've done it on planes (even in economy). I do use disk 7 of the learning course on my ipod to drown out background noise and give me something to direct my attention.
As for the embarrassment, this doesn't really bother me - flipping a book upside-down is not exactly anti-social behaviour.
I've not photoread in a bookshop or in a library though.
