Digital BW, The Print

Recently there was a posting that suggested that Bulldog had a 
destructive effect on watercolor papers. My question is, should I 
use Lyson Print Guard on papers like hahnemuhle William 
Turner or Luminos Museum Parchment or Legion Somerset 
enhanced?

What is the long term effect of Print guard. Does it eventually 
crack or discolor. I'm selling prints and while I always warn a 
purchaser that the surface of the print is fragile and should be 
placed under glass asap, I would like the added security of a 
protective spray if it didn't have a long term negative effect.

Mike