SATCOMER, thanks for bringing this up! The feature you are talking about is called
Windows Update Delivery Optimization it is designed to help users get updates faster. this feature is enabled by default in Windows 10 Home and Pro editions. On Windows 10 Enterprise and Education the feature is also enabled, but only for the local network.
I believe one can set this up to deliver updates from PCs on a local network, especially if there is a server in it.
I am not aware of any ISP in the USA that is currently enforcing bandwidth caps.
Cheers!