Since window cleaning is one of the last phases of construction, meeting deadlines for occupation requires the most efficient method, and scrapers have been part of that method for decades. 

So that windows can be cleaned efficiently with standard methods - not only after construction, but throughout the life of the home or building - builders, architects and remodelers are urged to specify that tempered glass surfaces be free of fabricating debris, and to indicate that any tempered glass with fabricating debris will be returned for a full and complete refund.  The International Window Cleaning Association is recommending that tempered glass be checked for fabricating debris before installation.

Certainly the ultimate owner of the new home or building deserves to know whether or not fabricating debris is present on tempered glass, because if it is, then vigilance will be required of them to somehow assure that scrapers are never used, or that the need to use scrapers never arises - for the life of the window. 

But it is sometimes suggested that the fabricating debris scratch problem is simply due to the use of scrapers by window cleaners who "should know better". Don't let anyone tell you that. The simple fact is that the use of window cleaning scrapers is widely accepted and embraced by professional window cleaners throughout the world.

One need only to look at the websites of professional quality squeegee manufacturers to see that their product lines include window cleaning scrapers. 

Ettore Products Company window cleaning product line includes squeegees as well as scrapers.

Pulex Cleaning Equipment  - window cleaning product line includes squeegees as well as scrapers.

Sörbo Products   - window cleaning product line includes squeegees as well as scrapers. 

Unger Enterprises  - window cleaning product line includes squeegees as well as scrapers.

And a quick look at major professional window cleaning supply catalogs shows the same thing. They sell window cleaning squeegees and scrapers.

Detroit Sponge & Chamois - sells squeegees and scrapers to window cleaners.

Squeegees.Net - sells squeegees and scrapers to window cleaners.

CWC Supply - sells squeegees and scrapers to window cleaners.

J. Racenstein & Company - sells squeegees and scrapers to window cleaners.

Furthermore, the largest supplier to the glazing industry - CR Laurence - actually sells a variety of scrapers.
An item in the CRL catalog called a window scraper (Catalog Number: 3223)  is described as "Very commonly used when scraping walls, windows, paint, and labels. From building maintenance to glaziers, and general contractors, all can benefit from these tools!"

One of the world's largest largest tool manufacturers - Stanley - sells scrapers, including one called a window scraper. (Search their site for "scraper".) Their Stanley Access Technologies division sells glass door and entry systems.

To bolster your argument that Professional Window Cleaners DO use scrapers, you can visit the above websites and print catalog pages.