Theives will do their best to avoid breaking glass, because it's more work than just
sliding a window open, and increases the chances of detection and injury.
Does that mean that when the burglar arrives at your humble adobe and
sees
that dowel you put there he'll turn around an go back home?
Me thinks he'll break your glass. A gentleman thief would first duct
tape
your glass so the pieces won't fall to the ground and less noise.
In fact a pry bar will suffice to lift the sliding door out of it's
channel.