Yep, the company I work for has been building test equipment with embedded pcs since the win2k days and has always just brought OEM licenses from a reseller no questions asked. In the ten years or so they have been doing that they have probably only build 100 systems.
I believe all that has happened recently is that anybody can now resell OEM copies to system builders and system builders is pretty loosely defined.
In the past you where not able to resell unless bundled with hardware.
That's why you can now buy OEM copies from pretty much any reputable retailer that sells parts, Amazon, scan, newegg, and so on.
By way of demonstration, he emitted a batlike squeak that was indeed bothersome.