Great question Brent!
I guess it depends on the motives of the guide... In my professional opinion, why not?! The way I look at it, it's a great educational/stewardship opportunity as "Interpretive info builds bridges between landscapes, people and history; reveals stories behind the scenery; and creates memorable and inspiring experiences". Is it always about catching (or is catching the bonus)? Could catching (or attempting to catch) pure strains lead to creating stewardship opportunities!? ABSOLUTELY!!
Lots of guides bring clients to areas that are environmentally sensitive and/or under a lot of angling pressure such as the Castle, Lynx, Carbondale, Liv, Upper Oldman, Upper Highwood, etc. I bet most don't provide any "interpretive", stewardship or educational info... (No judgement)...