And another: https://az792536.vo.msecnd.net/vms/release_notes_license_terms_8_1_15.pdf

Free means not activating the installation. There may be downsides to that, but most people in the ‘every once in a while for testing’ world won’t notice. It has long been the practice of Microsoft to allow users to test the OS before buying, but sometimes you just don’t know where to look through the forest of spam and trojan traps to find the One Safe One.

Good luck to us all.