If Slaughterhouses Had Glass Walls…

Saturday was the birthday of Linda Eastman McCartney (1942-1998), the US photographer and Beatle widow who said that

If slaughterhouses had glass walls the whole world would be vegetarian.

Of course, if Saddam's jails had had glass walls the whole world would have supported the war in Iraq, but that's not anything activists make much of these days, do they (and indeed, have they ever)?