This is more of a rant as can't think of a reason why he would do this.
We just rented a lovely 100 year old house. There are original stained glass windows going up the stairs which, in principle, are very pretty.
What I didn't know when I signed the lease is that rather than put in proper double glazing which I guess would be pricey if you wanted to keep the original windows, the landlord had just added a clear pane of glass in front of each window which you can't open.
That's bad enough - but he never cleaned the effing cobwebs or dusted before he did that!!! Every time I go up or down the stairs I want to smash the windows and clean the cobwebs.
Why, for the love of god, if you are about to seal your windows for posterity, wouldn't you take 5 minutes to dust.....????
And breathe....