There are 23 7-handed tables running with plexiglass separating the players at a local Arizona card-room tonight - been this way for at least 2 months, but I have no intention of going there anytime soon.
I think everyone who has played a lot of live poker has caught at least one 'casino cold' and knows how disgusting some of the players are.
If there's any evidence as to the efficacy of plexiglass I haven't seen it, and unless they are disinfecting everything and changing out the cards after every sneeze and nose-wipe I don't think see how it is a good idea, but to each their own.
Good luck!